Component positioning and encapsulation for sensor enabled wound dressings

ABSTRACT

Devices and methods for encapsulating a portion of a wound dressing with biocompatible coating are disclosed. In some embodiments, a method includes applying a first coating on a first side of a flexible substrate of the wound dressing. The first side of the substrate can support a plurality of electronic components, electronic tracks, and connectors between the electronic components and electronic tracks. The first coating can be applied to at least one connectors. The application of the first coating can strengthen the at least one connector. The method can further include applying a second biocompatible coating on the first side of the substrate of the wound dressing and coating a second side of the substrate opposite the first side with a third coating, and coating at least some of the plurality of the electronic components with a fourth coating.

BACKGROUND Field

Embodiments of the present disclosure relate to apparatuses, systems,and methods for the treatment of tissues via sensor-enabled monitoringin communication with various therapy regimes.

Description of the Related Art

Nearly all areas of medicine may benefit from improved informationregarding the state of the tissue, organ, or system to be treated,particularly if such information is gathered in real-time duringtreatment, many types of treatments are still routinely performedwithout the use of sensor data collection. Instead, such treatments relyupon visual inspection by a caregiver or other limited means rather thanquantitative sensor data. For example, in the case of wound treatmentvia dressings and/or negative pressure wound therapy, data collection isgenerally limited to visual inspection by a caregiver and often theunderlying wounded tissue may be obscured by bandages or other visualimpediments. Even intact, unwounded skin may have underlying damage thatis not visible to the naked eye, such as a compromised vascular ordeeper tissue damage that may lead to an ulcer. Similar to woundtreatment, during orthopedic treatments requiring the immobilization ofa limb with a cast or other encasement, only limited information isgathered on the underlying tissue. In instances of internal tissuerepair, such as a bone plate, continued direct sensor-driven datacollection is not performed. Further, braces and/or sleeves used tosupport musculoskeletal function do not monitor the functions of theunderlying muscles or the movement of the limbs. Outside of directtreatments, common hospital room items such as beds and blankets couldbe improved by adding capability to monitor patient parameters.

Therefore, there is a need for improved sensor monitoring, particularlythrough the use of sensor-enabled substrates which can be incorporatedinto existing treatment regimes.

SUMMARY

According to some embodiments, there is provided a method for coating awound dressing, the method comprising applying a first coating on afirst side of a substantially flexible wound contact layer of the wounddressing, the first side of the wound contact layer supporting aplurality of electronic components, electronic tracks, and connectorsbetween the electronic components and electronic tracks, wherein thefirst coating is applied to at least one connector of the plurality ofconnectors to reinforce the at least one connector, applying a secondcoating on the first side of the wound contact layer of the wounddressing, and coating a second side of the wound contact layer oppositethe first side with the second coating.

The method for coating a wound dressing described in any of thepreceding paragraphs may further comprise one or more of the followingfeatures. The method can further comprise applying the first coating toan area of the wound contact layer supporting and surrounding at leastone electronic component or electronic track electrically connected bythe at least one connector to reinforce the area of the wound contactlayer. The first coating can be applied to an area surrounding aperimeter of an electronic component associated with the at least oneconnector. The first coating can be applied to an area on a first sideof an electronic component where the at least one connector ispositioned and not applied on a second side of the electronic componentswhere the at least one connector is not positioned. The first coatingcan be applied in a strip pattern. The first coating can be applied in adot pattern. The second coating can comprise a hydrophobic coating. Thefirst and second coatings can comprise a biocompatible coating. Thewound contact layer can be formed at least partially from hydrophilicmaterial. The wound contact layer can be formed at least partially froma flexible material. The method can further comprise encapsulating thewound contact layer with the second coating. The first coating can besubstantially non-stretchable. The second coating can be substantiallystretchable. The method can further comprising coating at least some ofthe plurality of the electronic components with multiple layers of thesecond coating. Coating the first and second sides of the wound contactlayer with the second coating can comprise spraying the second coating.Spraying can comprise spraying with compressed air or inert gas. Thefirst coating can comprise at least one of Dymax 20351, Dymax 20558,Dymax 9001-E, or Loctite 3211. The first coating can have viscosity ofno more than about 50,000 centipoise.

According to some embodiments, there is provided a method for coating awound dressing, the method can comprise applying a first coating on afirst side of a substantially flexible substrate of the wound dressing,the first side of the substrate supporting a plurality of electroniccomponents, electronic tracks, and a plurality of connectors between theelectronic components and electronic tracks, wherein the first coatingis applied to at least one connector of the plurality of connectors toreinforce the at least one connector, applying a second coating on thefirst side of the substrate, coating a second side of the substrateopposite the first side with a third coating, and coating at least someof the plurality of the electronic components with a fourth coating.

The method for coating a wound dressing described in any of thepreceding paragraphs may further comprise one or more of the followingfeatures. The flexible substrate can be a flexible and extensiblesubstrate. The method can further comprise applying the first coating toa discrete area of the substrate supporting and surrounding at least oneelectronic component or electronic track electrically connected by theat least one connector to reinforce the area of the substrate. Themethod wherein the first coating can be applied to an area surrounding aperimeter of an electronic component associated with the at least oneconnector. The method wherein the first coating can be applied to anarea on a first side of an electronic component where the at least oneconnector is positioned and not applied on a second side of theelectronic components where the at least one connector is notpositioned. The first coating can be applied in a strip pattern. Thefirst coating can be applied in a dot pattern. The second coating cancomprise a hydrophobic coating. The second coating can comprise ahydrophilic coating. The second coating can comprise a thickness ofbetween 10-200 μm. The second coating can comprise a thickness ofbetween 18-130 μm. The first, second, third, and/or fourth coatings cancomprise a biocompatible coating. The second coating can comprise abiocompatible coating. The first and second coatings can comprise abiocompatible coating. The second coating and the third coating can bethe same material. The second coating and the fourth coating can be thesame material. The second coating, the third coating, and fourth coatingcan be the same material. The substrate can be formed at least partiallyfrom hydrophilic material. The substrate can be formed at leastpartially from hydrophobic material. The substrate can be formed atleast partially from a flexible material. The substrate can be formed atleast partially from an extensible material. The method can furthercomprise encapsulating the substrate with the second coating. The firstcoating can be substantially non-stretchable. The second coating can besubstantially stretchable. The third coating can be substantiallystretchable. The fourth coating can be substantially stretchable. Themethod can further comprise coating at least some of the plurality ofthe electronic components with multiple layers of the first, second,third, and/or fourth coating. Coating the first and second sides of thesubstrate with the second and third coatings can comprise spraying thesecond and third coatings. Spraying can comprise spraying withcompressed air or inert gas. Handling and curing of the material canoccur under inert atmosphere techniques. The first coating can compriseat least one of Dymax 20351, Dymax 20558, Dymax 9001-E, or Loctite 3211.The first coating can have a viscosity of no more than about 50,000centipoise. The first coating can be applied to an area around aperimeter of an electronic component at areas not associated with the atleast one connector. The first coating can be applied to the edge of acomponent of the plurality of electronic components to reinforce theedge of the component and the at least one connector of the plurality ofconnectors.

According to some embodiments, there is provided a wound dressingapparatus comprising a substantially flexible substrate. The substratecan comprise a first side of the substrate supporting a plurality ofelectronic components, electronic tracks, and a plurality of connectorsbetween the electronic components and electronic tracks, a first coatingon the first side of the substrate applied to at least one connector ofthe plurality of connectors to reinforce the at least one connector, asecond coating on the first side of the substrate, a third coating on asecond side of the substrate opposite the first side, and a fourthcoating applied over at least some of the plurality of the electroniccomponents.

The wound dressing apparatus described in any of the precedingparagraphs may further comprise one or more of the following features.The flexible substrate can be a flexible and extensible substrate. Thefirst coating can be applied to a discrete area of the substratesupporting and surrounding at least one electronic component orelectronic track electrically connected by the at least one connector toreinforce the area of the substrate. The first coating can be applied toan area surrounding a perimeter of an electronic component associatedwith the at least one connector. The first coating can be applied to anarea on a first side of an electronic component where the at least oneconnector is positioned and not applied on a second side of theelectronic components where the at least one connector is notpositioned. The first coating can be substantially non-stretchable. Thesecond coating can be substantially stretchable. The third coating canbe substantially stretchable. The fourth coating can be substantiallystretchable. At least some of the plurality of the electronic componentscan be coated with multiple layers of the first, second, third, and/orfourth coating. The second coating and the third coating can be the samematerial. The second coating and the fourth coating can be the samematerial. The second coating, the third coating, and fourth coating canbe the same material. The substrate can be encapsulated with the secondcoating.

Other embodiments of a wound dressing, devices, kits and associatedmethods are described below.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will now be described hereinafter,by way of example only, with reference to the accompanying drawings inwhich:

FIG. 1A illustrates a negative pressure wound treatment system accordingto some embodiments;

FIG. 1B illustrates a wound dressing according to some embodiments;

FIG. 2 illustrates a sensor array illustrating the sensor placementincorporated into a wound dressing according to some embodiments;

FIG. 3A illustrates a flexible sensor array including a sensor arrayportion, a tail portion and a connector pad end portion according tosome embodiments;

FIG. 3B illustrates flexible circuit boards with different sensor arraygeometries according to some embodiments;

FIG. 3C illustrates the sensor array portion of a sensor array shown inFIG. 3B;

FIG. 3D illustrates a flexible sensor array incorporated into aperforated wound contact layer according to some embodiments;

FIG. 3E illustrates a control module according to some embodiments;

FIGS. 4A-4C illustrate a wound dressing with a plurality of electroniccomponents according to some embodiments;

FIGS. 5A-5B illustrate coating(s) of a wound dressing according to someembodiments;

FIG. 6 illustrates coating a wound dressing with two biocompatiblecoatings according to some embodiments;

FIG. 7 illustrates coating a wound dressing with a biocompatible coatingaccording to some embodiments;

FIG. 8 illustrates a device for coating a wound dressing according tosome embodiments;

FIG. 9 illustrates spray coating a wound dressing according to someembodiments;

FIG. 10 illustrates a mold for coating a wound dressing according tosome embodiments;

FIG. 11 illustrates another device for coating a wound dressingaccording to some embodiments;

FIGS. 12A-12B illustrate an assembled device for coating a wounddressing according to some embodiments;

FIG. 13 illustrates release liner for coating a wound dressing accordingto some embodiments;

FIGS. 14A-14B illustrate coating a wound dressing according to someembodiments;

FIG. 15 illustrates spray coating a wound dressing according to someembodiments;

FIG. 16 illustrates applying non-stretchable material to a wounddressing according to some embodiments;

FIGS. 17A-17B illustrate comparisons of performance without and withnon-stretchable material according to some embodiments;

FIG. 18 illustrates a wound dressing with one or more perforationsaccording to some embodiments;

FIGS. 19A-B illustrate coating a wound dressing with one or moreperforations according to some embodiments;

FIGS. 20A-20B illustrates a portion of a wound dressing with a pluralityof electronic components according to some embodiments;

FIGS. 21A-21D illustrate different application patterns of coatingmaterial on a substrate of a wound dressing;

FIGS. 22-23 illustrates coating(s) of a wound dressing according to someembodiments; and

FIGS. 24A-24B illustrate embodiments of a substrate of a wound dressingwith a plurality of electronic components with coating(s).

DETAILED DESCRIPTION

Embodiments disclosed herein relate to apparatuses and methods ofmonitoring and treating biological tissue with sensor-enabledsubstrates. The embodiments disclosed herein are not limited totreatment or monitoring of a particular type of tissue or injury,instead the sensor-enabled technologies disclosed herein are broadlyapplicable to any type of therapy that may benefit from sensor-enabledsubstrates. Some implementations utilize sensors and data collectionrelied upon by health care providers to make both diagnostic and patientmanagement decisions.

Some embodiments disclosed herein relate to the use of sensors mountedon or embedded within substrates configured to be used in the treatmentof both intact and damaged human or animal tissue. Such sensors maycollect information about the surrounding tissue and transmit suchinformation to a computing device or a caregiver to be utilized infurther treatment. In certain embodiments, such sensors may be attachedto the skin anywhere on the body, including areas for monitoringarthritis, temperature, or other areas that may be prone to problems andrequire monitoring. Sensors disclosed herein may also incorporatemarkers, such as radiopaque markers, to indicate the presence of thedevice, for example prior to performing an MRI or other technique.

The sensor embodiments disclosed herein may be used in combination withclothing. Non-limiting examples of clothing for use with embodiments ofthe sensors disclosed herein include shirts, pants, trousers, dresses,undergarments, outer-garments, gloves, shoes, hats, and other suitablegarments. In certain embodiments, the sensor embodiments disclosedherein may be welded into or laminated into/onto the particulargarments. The sensor embodiments may be printed directly onto thegarment and/or embedded into the fabric. Breathable and printablematerials such as microporous membranes may also be suitable.

Sensor embodiments disclosed herein may be incorporated into cushioningor bed padding, such as within a hospital bed, to monitor patientcharacteristics, such as any characteristic disclosed herein. In certainembodiments, a disposable film containing such sensors could be placedover the hospital bedding and removed/replaced as needed.

In some implementations, the sensor embodiments disclosed herein mayincorporate energy harvesting, such that the sensor embodiments areself-sustaining. For example, energy may be harvested from thermalenergy sources, kinetic energy sources, chemical gradients, or anysuitable energy source.

The sensor embodiments disclosed herein may be utilized inrehabilitation devices and treatments, including sports medicine. Forexample, the sensor embodiments disclosed herein may be used in braces,sleeves, wraps, supports, and other suitable items. Similarly, thesensor embodiments disclosed herein may be incorporated into sportingequipment, such as helmets, sleeves, and/or pads. For example, suchsensor embodiments may be incorporated into a protective helmet tomonitor characteristics such as acceleration, which may be useful inconcussion diagnosis.

The sensor embodiments disclosed herein may be used in coordination withsurgical devices, for example, the NAVIO surgical system by Smith &Nephew Inc. In implementations, the sensor embodiments disclosed hereinmay be in communication with such surgical devices to guide placement ofthe surgical devices. In some implementations, the sensor embodimentsdisclosed herein may monitor blood flow to or away from the potentialsurgical site or ensure that there is no blood flow to a surgical site.Further surgical data may be collected to aid in the prevention ofscarring and monitor areas away from the impacted area.

To further aid in surgical techniques, the sensors disclosed herein maybe incorporated into a surgical drape to provide information regardingtissue under the drape that may not be immediately visible to the nakedeye. For example, a sensor embedded flexible drape may have sensorspositioned advantageously to provide improved area-focused datacollection. In certain implementations, the sensor embodiments disclosedherein may be incorporated into the border or interior of a drape tocreate fencing to limit/control the surgical theater.

Sensor embodiments as disclosed herein may also be utilized forpre-surgical assessment. For example, such sensor embodiments may beused to collect information about a potential surgical site, such as bymonitoring skin and the underlying tissues for a possible incision site.For example, perfusion levels or other suitable characteristics may bemonitored at the surface of the skin and deeper in the tissue to assesswhether an individual patient may be at risk for surgical complications.Sensor embodiments such as those disclosed herein may be used toevaluate the presence of microbial infection and provide an indicationfor the use of antimicrobials. Further, sensor embodiments disclosedherein may collect further information in deeper tissue, such asidentifying pressure ulcer damage and/or the fatty tissue levels.

The sensor embodiments disclosed herein may be utilized incardiovascular monitoring. For example, such sensor embodiments may beincorporated into a flexible cardiovascular monitor that may be placedagainst the skin to monitor characteristics of the cardiovascular systemand communicate such information to another device and/or a caregiver.For example, such a device may monitor pulse rate, oxygenation of theblood, and/or electrical activity of the heart. Similarly, the sensorembodiments disclosed herein may be utilized for neurophysiologicalapplications, such as monitoring electrical activity of neurons.

The sensor embodiments disclosed herein may be incorporated intoimplantable devices, such as implantable orthopedic implants, includingflexible implants. Such sensor embodiments may be configured to collectinformation regarding the implant site and transmit this information toan external source. In some embodiments, an internal source may alsoprovide power for such an implant.

The sensor embodiments disclosed herein may also be utilized formonitoring biochemical activity on the surface of the skin or below thesurface of the skin, such as lactose buildup in muscle or sweatproduction on the surface of the skin. In some embodiments, othercharacteristics may be monitored, such as glucose concentration, urineconcentration, tissue pressure, skin temperature, skin surfaceconductivity, skin surface resistivity, skin hydration, skin maceration,and/or skin ripping.

Sensor embodiments as disclosed herein may be incorporated into Ear,Nose, and Throat (ENT) applications. For example, such sensorembodiments may be utilized to monitor recovery from ENT-relatedsurgery, such as wound monitoring within the sinus passage.

As described in greater detail below, the sensor embodiments disclosedherein may encompass sensor printing technology with encapsulation, suchas encapsulation with a polymer film. Such a film may be constructedusing any polymer described herein, such as polyurethane. Encapsulationof the sensor embodiments may provide waterproofing of the electronicsand protection from local tissue, local fluids, and other sources ofpotential damage.

In certain embodiments, the sensors disclosed herein may be incorporatedinto an organ protection layer such as disclosed below. Such asensor-embedded organ protection layer may both protect the organ ofinterest and confirm that the organ protection layer is in position andproviding protection. Further, a sensor-embedded organ protection layermay be utilized to monitor the underlying organ, such as by monitoringblood flow, oxygenation, and other suitable markers of organ health. Insome embodiments, a sensor-enabled organ protection layer may be used tomonitor a transplanted organ, such as by monitoring the fat and musclecontent of the organ. Further, sensor-enabled organ protection layersmay be used to monitor an organ during and after transplant, such asduring rehabilitation of the organ.

The sensor embodiments disclosed herein may be incorporated intotreatments for wounds (disclosed in greater detail below) or in avariety of other applications. Non-limiting examples of additionalapplications for the sensor embodiments disclosed herein include:monitoring and treatment of intact skin, cardiovascular applicationssuch as monitoring blood flow, orthopedic applications such asmonitoring limb movement and bone repair, neurophysiologicalapplications such as monitoring electrical impulses, and any othertissue, organ, system, or condition that may benefit from improvedsensor-enabled monitoring.

Wound Therapy

Some embodiments disclosed herein relate to wound therapy for a human oranimal body. Therefore, any reference to a wound herein can refer to awound on a human or animal body, and any reference to a body herein canrefer to a human or animal body. The disclosed technology embodimentsmay relate to preventing or minimizing damage to physiological tissue orliving tissue, or to the treatment of damaged tissue (for example, awound as described herein) wound with or without reduced pressure,including for example a source of negative pressure and wound dressingcomponents and apparatuses. The apparatuses and components comprisingthe wound overlay and packing materials or internal layers, if any, aresometimes collectively referred to herein as dressings. In someembodiments, the wound dressing can be provided to be utilized withoutreduced pressure.

Some embodiments disclosed herein relate to wound therapy for a human oranimal body. Therefore, any reference to a wound herein can refer to awound on a human or animal body, and any reference to a body herein canrefer to a human or animal body. The disclosed technology embodimentsmay relate to preventing or minimizing damage to physiological tissue orliving tissue, or to the treatment of damaged tissue (for example, awound as described herein).

As used herein the expression “wound” may include an injury to livingtissue may be caused by a cut, blow, or other impact, typically one inwhich the skin is cut or broken. A wound may be a chronic or acuteinjury. Acute wounds occur as a result of surgery or trauma. They movethrough the stages of healing within a predicted timeframe. Chronicwounds typically begin as acute wounds. The acute wound can become achronic wound when it does not follow the healing stages resulting in alengthened recovery. It is believed that the transition from acute tochronic wound can be due to a patient being immuno-compromised.

Chronic wounds may include for example: venous ulcers (such as thosethat occur in the legs), which account for the majority of chronicwounds and mostly affect the elderly, diabetic ulcers (for example, footor ankle ulcers), peripheral arterial disease, pressure ulcers, orepidermolysis bullosa (EB).

Examples of other wounds include, but are not limited to, abdominalwounds or other large or incisional wounds, either as a result ofsurgery, trauma, sternotomies, fasciotomies, or other conditions,dehisced wounds, acute wounds, chronic wounds, subacute and dehiscedwounds, traumatic wounds, flaps and skin grafts, lacerations, abrasions,contusions, bums, diabetic ulcers, pressure ulcers, stoma, surgicalwounds, trauma and venous ulcers or the like.

Wounds may also include a deep tissue injury. Deep tissue injury is aterm proposed by the National Pressure Ulcer Advisory Panel (NPUAP) todescribe a unique form of pressure ulcers. These ulcers have beendescribed by clinicians for many years with terms such as purplepressure ulcers, ulcers that are likely to deteriorate and bruises onbony prominences.

Wound may also include tissue at risk of becoming a wound as discussedherein. For example, tissue at risk may include tissue over a bonyprotuberance (at risk of deep tissue injury/insult) or pre-surgicaltissue (for example, knee tissue) that may have the potential to be cut(for example, for joint replacement/surgical alteration/reconstruction).

Some embodiments relate to methods of treating a wound with thetechnology disclosed herein in conjunction with one or more of thefollowing: advanced footwear, turning a patient, offloading (such as,offloading diabetic foot ulcers), treatment of infection, systemics,antimicrobial, antibiotics, surgery, removal of tissue, affecting bloodflow, physiotherapy, exercise, bathing, nutrition, hydration, nervestimulation, ultrasound, electrostimulation, oxygen therapy, microwavetherapy, active agents ozone, antibiotics, antimicrobials, or the like.

Alternatively or additionally, a wound may be treated using topicalnegative pressure and/or traditional advanced wound care, which is notaided by the using of applied negative pressure (may also be referred toas non-negative pressure therapy).

Advanced wound care may include use of an absorbent dressing, anocclusive dressing, use of an antimicrobial and/or debriding agents in awound dressing or adjunct, a pad (for example, a cushioning orcompressive therapy, such as stockings or bandages), or the like.

In some embodiments, treatment of such wounds can be performed usingtraditional wound care, wherein a dressing can be applied to the woundto facilitate and promote healing of the wound.

Some embodiments relate to methods of manufacturing a wound dressingcomprising providing a wound dressing as disclosed herein.

The wound dressings that may be utilized in conjunction with thedisclosed technology include any known dressing in the art. Thetechnology is applicable to negative pressure therapy treatment as wellas non-negative pressure therapy treatment.

In some embodiments, a wound dressing comprises one or more absorbentlayer(s). The absorbent layer may be a foam or a superabsorbent.

In some embodiments, wound dressings may comprise a dressing layerincluding a polysaccharide or modified polysaccharide, apolyvinylpyrrolidone, a polyvinyl alcohol, a polyvinyl ether, apolyurethane, a polyacrylate, a polyacrylamide, collagen, or gelatin ormixtures thereof. Dressing layers comprising the polymers listed areknown in the art as being useful for forming a wound dressing layer foreither negative pressure therapy or non-negative pressure therapy.

In some embodiments, the polymer matrix may be a polysaccharide ormodified polysaccharide.

In some embodiments, the polymer matrix may be a cellulose. Cellulosematerial may include hydrophilically modified cellulose such as methylcellulose, carboxymethyl cellulose (CMC), carboxymethyl cellulose (CEC),ethyl cellulose, propyl cellulose, hydroxyethyl cellulose, hydroxypropylcellulose, hydroxypropylmethyl cellulose, carboxyethyl sulphonatecellulose, cellulose alkyl sulphonate, or mixtures thereof.

In certain embodiments, cellulose material may be cellulose alkylsulphonate. The alkyl moiety of the alkyl sulphonate substituent groupmay have an alkyl group having 1 to 6 carbon atoms, such as methyl,ethyl, propyl, or butyl. The alkyl moiety may be branched or unbranched,and hence suitable propyl sulphonate substituents may be 1- or2-methyl-ethylsulphonate. Butyl sulphonate substituents may be2-ethyl-ethylsulphonate, 2,2-dimethyl-ethylsulphonate, or1,2-dimethyl-ethylsulphonate. The alkyl sulphonate substituent group maybe ethyl sulphonate. The cellulose alkyl sulphonate is described inWO10061225, US2016/114074, US2006/0142560, or U.S. Pat. No. 5,703,225,the disclosures of which are hereby incorporated by reference in theirentirety.

Cellulose alkyl sulfonates may have varying degrees of substitution, thechain length of the cellulose backbone structure, and the structure ofthe alkyl sulfonate substituent. Solubility and absorbency are largelydependent on the degree of substitution: as the degree of substitutionis increased, the cellulose alkyl sulfonate becomes increasinglysoluble. It follows that, as solubility increases, absorbency increases.

In some embodiments, a wound dressing also comprises a top or coverlayer. The thickness of the wound dressing disclosed herein may bebetween 1 to 20, or 2 to 10, or 3 to 7 mm.

In some embodiments, the disclosed technology may be used in conjunctionwith a non-negative pressure dressing. A non-negative pressure wounddressing suitable for providing protection at a wound site may comprise:

an absorbent layer for absorbing wound exudate and

an obscuring element for at least partially obscuring a view of woundexudate absorbed by the absorbent layer in use.

The obscuring element may be partially translucent.

The obscuring element may be a masking layer.

The non-negative pressure wound dressing may further comprise a regionin or adjacent the obscuring element for allowing viewing of theabsorbent layer. For example, the obscuring element layer may beprovided over a central region of the absorbent layer and not over aborder region of the absorbent layer. In some embodiments, the obscuringelement is of hydrophilic material or is coated with a hydrophilicmaterial.

The obscuring element may comprise a three-dimensional knitted spacerfabric. The spacer fabric is known in the art and may include a knittedspacer fabric layer.

The obscuring element may further comprise an indicator for indicatingthe need to change the dressing.

In some embodiments, the obscuring element is provided as a layer atleast partially over the absorbent layer, further from a wound site thanthe absorbent layer in use.

The non-negative pressure wound dressing may further comprise aplurality of openings in the obscuring element for allowing fluid tomove therethrough. The obscuring element may comprise, or may be coatedwith, a material having size-exclusion properties for selectivelypermitting or preventing passage of molecules of a predetermined size orweight.

The obscuring element may be configured to at least partially mask lightradiation having wavelength of 600 nm and less.

The obscuring element may be configured to reduce light absorption by50% or more.

The obscuring element may be configured to yield a CIE L* value of 50 ormore, and optionally 70 or more. In some embodiments, the obscuringelement may be configured to yield a CIE L* value of 70 or more.

In some embodiments, the non-negative pressure wound dressing mayfurther comprise at least one of a wound contact layer, a foam layer, anodor control element, a pressure-resistant layer and a cover layer.

In some embodiments, the cover layer is present, and the cover layer isa translucent film. Typically, the translucent film has a moisturevapour permeability of 500 g/m2/24 hours or more.

The translucent film may be a bacterial barrier.

In some embodiments, the non-negative pressure wound dressing asdisclosed herein comprises the wound contact layer and the absorbentlayer overlies the wound contact layer. The wound contact layer carriesan adhesive portion for forming a substantially fluid tight seal overthe wound site.

The non-negative pressure wound dressing as disclosed herein maycomprise the obscuring element and the absorbent layer being provided asa single layer.

In some embodiments, the non-negative pressure wound dressing disclosedherein comprises the foam layer, and the obscuring element is of amaterial comprising components that may be displaced or broken bymovement of the obscuring element.

In some embodiments, the non-negative pressure wound dressing comprisesan odor control element, and in another embodiment the dressing does notinclude an odor control element. When present, the odor control elementmay be dispersed within or adjacent the absorbent layer or the obscuringelement. Alternatively, when present the odor control element may beprovided as a layer sandwiched between the foam layer and the absorbentlayer.

In some embodiments, the disclosed technology for a non-negativepressure wound dressing comprises a method of manufacturing a wounddressing, comprising: providing an absorbent layer for absorbing woundexudate; and providing an obscuring element for at least partiallyobscuring a view of wound exudate absorbed by the absorbent layer inuse.

In some embodiments, the non-negative pressure wound dressing is may besuitable for providing protection at a wound site, comprising: anabsorbent layer for absorbing wound exudate; and a shielding layerprovided over the absorbent layer, and further from a wound-facing sideof the wound dressing than the absorbent layer. The shielding layer maybe provided directly over the absorbent layer. In some embodiments, theshielding layer comprises a three-dimensional spacer fabric layer.

The shielding layer increases the area over which a pressure applied tothe dressing is transferred by 25% or more or the initial area ofapplication. For example, the shielding layer increases the area overwhich a pressure applied to the dressing is transferred by 50% or more,and optionally by 100% or more, and optionally by 200% or more.

The shielding layer may comprise 2 or more sub-layers, wherein a firstsub-layer comprises through holes and a further sub-layer comprisesthrough holes and the through holes of the first sub-layer are offsetfrom the through holes of the further sub-layer.

The non-negative pressure wound dressing as disclosed herein may furthercomprise a permeable cover layer for allowing the transmission of gasand vapour therethrough, the cover layer provided over the shieldinglayer, wherein through holes of the cover layer are offset from throughholes of the shielding layer.

The non-negative pressure wound dressing may be suitable for treatmentof pressure ulcers.

A more detailed description of the non-negative pressure dressingdisclosed hereinabove is provided in WO2013007973, the entirety of whichis hereby incorporated by reference.

In some embodiments, the non-negative pressure wound dressing may be amulti-layered wound dressing comprising: a fibrous absorbent layer forabsorbing exudate from a wound site; and a support layer configured toreduce shrinkage of at least a portion of the wound dressing.

In some embodiments, the multi-layered wound dressing disclosed herein,further comprises a liquid impermeable film layer, wherein the supportlayer is located between the absorbent layer and the film layer.

The support layer disclosed herein may comprise a net. The net maycomprise a geometric structure having a plurality of substantiallygeometric apertures extending therethrough. The geometric structure mayfor example comprise a plurality of bosses substantially evenly spacedand joined by polymer strands to form the substantially geometricapertures between the polymer strands.

The net may be formed from high density polyethylene.

The apertures may have an area from 0.005 to 0.32 mm2.

The support layer may have a tensile strength from 0.05 to 0.06 Nm.

The support layer may have a thickness of from 50 to 150 μm.

In some embodiments, the support layer is located directly adjacent theabsorbent layer. Typically, the support layer is bonded to fibers in atop surface of the absorbent layer. The support layer may furthercomprise a bonding layer, wherein the support layer is heat laminated tothe fibers in the absorbent layer via the bonding layer. The bondinglayer may comprise a low melting point adhesive such as ethylene-vinylacetate adhesive.

In some embodiments, the multi-layered wound dressing disclosed hereinfurther comprises an adhesive layer attaching the film layer to thesupport layer.

In some embodiments, the multi-layered wound dressing disclosed hereinfurther comprises a wound contact layer located adjacent the absorbentlayer for positioning adjacent a wound. The multi-layered wound dressingmay further comprise a fluid transport layer between the wound contactlayer and the absorbent layer for transporting exudate away from a woundinto the absorbent layer.

A more detailed description of the multi-layered wound dressingdisclosed hereinabove is provided in GB patent application filed on 28Oct. 2016 with application number GB1618298.2, the entirety of which ishereby incorporated by reference.

In some embodiments, the disclosed technology may be incorporated in awound dressing comprising a vertically lapped material comprising: afirst layer of an absorbing layer of material, and a second layer ofmaterial, wherein the first layer being constructed from at least onelayer of non-woven textile fibers, the non-woven textile fibers beingfolded into a plurality of folds to form a pleated structure. In someembodiments, the wound dressing further comprises a second layer ofmaterial that is temporarily or permanently connected to the first layerof material.

Typically the vertically lapped material has been slitted.

In some embodiments, the first layer has a pleated structure having adepth determined by the depth of pleats or by the slitting width. Thefirst layer of material may be a moldable, lightweight, fiber-basedmaterial, blend of material or composition layer.

The first layer of material may comprise one or more of manufacturedfibers from synthetic, natural or inorganic polymers, natural fibers ofa cellulosic, proteinaceous or mineral source.

The wound dressing may comprise two or more layers of the absorbinglayer of material vertically lapped material stacked one on top of theother, wherein the two or more layers have the same or differentdensities or composition.

The wound dressing may in some embodiments comprise only one layer ofthe absorbing layer of material vertically lapped material.

The absorbing layer of material is a blend of natural or synthetic,organic or inorganic fibers, and binder fibers, or bicomponent fiberstypically PET with a low melt temperature PET coating to soften atspecified temperatures and to act as a bonding agent in the overallblend.

In some embodiments, the absorbing layer of material may be a blend of 5to 95% thermoplastic polymer, and 5 to 95 wt % of a cellulose orderivative thereof.

In some embodiments, the wound dressing disclosed herein has a secondlayer comprises a foam or a dressing fixative.

The foam may be a polyurethane foam. The polyurethane foam may have anopen or closed pore structure.

The dressing fixative may include bandages, tape, gauze, or backinglayer.

In some embodiments, the wound dressing as disclosed herein comprisesthe absorbing layer of material connected directly to a second layer bylamination or by an adhesive, and the second layer is connected to adressing fixative layer. The adhesive may be an acrylic adhesive, or asilicone adhesive.

In some embodiments, the wound dressing as disclosed herein furthercomprises layer of a superabsorbent fiber, or a viscose fiber or apolyester fiber.

In some embodiments, the wound dressing as disclosed herein furthercomprises a backing layer. The backing layer may be a transparent oropaque film. Typically, the backing layer comprises a polyurethane film(typically a transparent polyurethane film).

A more detailed description of the multi-layered wound dressingdisclosed hereinabove is provided in GB patent applications filed on 12Dec. 2016 with application number GB1621057.7; and 22 Jun. 2017 withapplication number GB1709987.0, the entirety of each of which is herebyincorporated by reference.

In some embodiments, the non-negative pressure wound dressing maycomprise an absorbent component for a wound dressing, the componentcomprising a wound contacting layer comprising gel forming fibers boundto a foam layer, wherein the foam layer is bound directly to the woundcontact layer by an adhesive, polymer based melt layer, by flamelamination or by ultrasound.

The absorbent component may be in a sheet form.

The wound contacting layer may comprise a layer of woven or non-woven orknitted gel forming fibers.

The foam layer may be an open cell foam, or closed cell foam, typicallyan open cell foam. The foam layer is a hydrophilic foam.

The wound dressing may comprise the component that forms an island indirect contact with the wound surrounded by periphery of adhesive thatadheres the dressing to the wound. The adhesive may be a silicone oracrylic adhesive, typically a silicone adhesive.

The wound dressing may be covered by a film layer on the surface of thedressing furthest from the wound.

A more detailed description of the wound dressing of this typehereinabove is provided in EP2498829, the entirety of which is herebyincorporated by reference.

In some embodiments, the non-negative pressure wound dressing maycomprise a multi layered wound dressing for use on wounds producing highlevels of exudate, characterized in that the dressing comprising: atransmission layer having an MVTR of at least 300 gm2/24 hours, anabsorbent core comprising gel forming fibers capable of absorbing andretaining exudate, a wound contacting layer comprising gel formingfibers which transmits exudate to the absorbent core and a keying layerpositioned on the absorbent core, the absorbent core and woundcontacting layer limiting the lateral spread of exudate in the dressingto the region of the wound.

The wound dressing may be capable of handling at least 6 g (or 8 g and15 g) of fluid per 10 cm2 of dressing in 24 hours.

The wound dressing may comprise gel forming fibers that are chemicallymodified cellulosic fibers in the form of a fabric. The fibers mayinclude carboxymethylated cellulose fibers, typically sodiumcarboxymethylcellulose fiber.

The wound dressing may comprise a wound contact layer with a lateralwicking rate from 5 mm per minute to 40 mm per minute. The wound contactlayer may have a fiber density between 25 gm2 and 55 gm2, such as 35gm2.

The absorbent core may have an absorbency of exudate of at least 10 g/g,and typically a rate of lateral wicking of less the 20 mm per minute.

The absorbent core may have a blend in the range of up to 25% cellulosicfibers by weight and 75% to 100% gel forming fibers by weight.

Alternatively, the absorbent core may have a blend in the range of up to50% cellulosic fibers by weight and 50% to 100% gel forming fibers byweight. For example, the blend is in the range of 50% cellulosic fibersby weight and 50% gel forming fibers by weight.

The fiber density in the absorbent core may be between 150 gm2 and 250gm2, or about 200 gm2.

The wound dressing when wet may have shrinkage that is less than 25% orless than 15% of its original size/dimension.

The wound dressing may comprise a transmission layer and the layer is afoam. The transmission layer may be a polyurethane foam laminated to apolyurethane film.

The wound dressing may comprise one or more layers selected from thegroup comprising a soluble medicated film layer; an odor-absorbinglayer; a spreading layer and an additional adhesive layer.

The wound dressing may be 2 mm and 4 mm thick.

The wound dressing may be characterized in that the keying layer bondsthe absorbent core to a neighboring layer. In some embodiments, thekeying layer may be positioned on either the wound facing side of theabsorbent core or the non-wound facing side of the absorbent core. Insome embodiments, the keying layer is positioned between the absorbentcore and the wound contact layer. The keying layer is a polyamide web.

A more detailed description of the wound dressing of this typehereinabove is provided in EP1718257, the entirety of which is herebyincorporated by reference.

In some embodiments, the non-negative pressure wound dressing may be acompression bandage. Compression bandages are known for use in thetreatment of oedema and other venous and lymphatic disorders, e.g., ofthe lower limbs.

A compression bandage systems typically employ multiple layers includinga padding layer between the skin and the compression layer or layers.The compression bandage may be useful for wounds such as handling venousleg ulcers.

The compression bandage in some embodiments may comprise a bandagesystem comprising an inner skin facing layer and an elastic outer layer,the inner layer comprising a first ply of foam and a second ply of anabsorbent nonwoven web, the inner layer and outer layer beingsufficiently elongated so as to be capable of being wound about apatient's limb. A compression bandage of this type is disclosed inWO99/58090, the entirety of which is hereby incorporated by reference.

In some embodiments, the compression bandage system comprises: a) aninner skin facing, elongated, elastic bandage comprising: (i) anelongated, elastic substrate, and

-   -   (ii) an elongated layer of foam, said foam layer being affixed        to a face of said substrate and extending 33% or more across        said face of substrate in transverse direction and 67% or more        across said face of substrate in longitudinal direction; and b)        an outer, elongated, self-adhering elastic bandage; said bandage        having a compressive force when extended; wherein, in use, said        foam layer of the inner bandage faces the skin and the outer        bandage overlies the inner bandage. A compression bandage of        this type is disclosed in WO2006/110527, the entirety of which        is hereby incorporated by reference.

In some embodiments other compression bandage systems such as thosedisclosed in U.S. Pat. No. 6,759,566 and US 2002/0099318, the entiretyof each of which is hereby incorporated by reference.

Negative Pressure Wound Dressing

In some embodiments, treatment of such wounds can be performed usingnegative pressure wound therapy, wherein a reduced or negative pressurecan be applied to the wound to facilitate and promote healing of thewound. It will also be appreciated that the wound dressing and methodsas disclosed herein may be applied to other parts of the body, and arenot necessarily limited to treatment of wounds.

It will be understood that embodiments of the present disclosure aregenerally applicable to use in topical negative pressure (“TNP”) therapysystems. Briefly, negative pressure wound therapy assists in the closureand healing of many forms of “hard to heal” wounds by reducing tissueoedema; encouraging blood flow and granular tissue formation; removingexcess exudate and may reduce bacterial load (and thus infection risk).In addition, the therapy allows for less disturbance of a wound leadingto more rapid healing. TNP therapy systems may also assist on thehealing of surgically closed wounds by removing fluid and by helping tostabilize the tissue in the apposed position of closure. A furtherbeneficial use of TNP therapy can be found in grafts and flaps whereremoval of excess fluid is important and close proximity of the graft totissue is required in order to ensure tissue viability.

Negative pressure therapy can be used for the treatment of open orchronic wounds that are too large to spontaneously close or otherwisefail to heal by means of applying negative pressure to the site of thewound. Topical negative pressure (TNP) therapy or negative pressurewound therapy (NPWT) involves placing a cover that is impermeable orsemi-permeable to fluids over the wound, using various means to seal thecover to the tissue of the patient surrounding the wound, and connectinga source of negative pressure (such as a vacuum pump) to the cover in amanner so that negative pressure is created and maintained under thecover. It is believed that such negative pressures promote wound healingby facilitating the formation of granulation tissue at the wound siteand assisting the body's normal inflammatory process whilesimultaneously removing excess fluid, which may contain adversecytokines or bacteria.

Some of the dressings used in NPWT can include many different types ofmaterials and layers, for example, gauze, pads, foam pads or multi-layerwound dressings. One example of a multi-layer wound dressing is the PICOdressing, available from Smith & Nephew, includes a wound contact layerand a superabsorbent layer beneath a backing layer to provide acanister-less system for treating a wound with NPWT. The wound dressingmay be sealed to a suction port providing connection to a length oftubing, which may be used to pump fluid out of the dressing or totransmit negative pressure from a pump to the wound dressing.Additionally, RENASYS-F, RENASYS-G, RENASYS-AB, and RENASYS-F/AB,available from Smith & Nephew, are additional examples of NPWT wounddressings and systems. Another example of a multi-layer wound dressingis the ALLEVYN Life dressing, available from Smith & Nephew, whichincludes a moist wound environment dressing that is used to treat thewound without the use of negative pressure.

As is used herein, reduced or negative pressure levels, such as −X mmHg,represent pressure levels relative to normal ambient atmosphericpressure, which can correspond to 760 mmHg (or 1 atm, 29.93 inHg,101.325 kPa, 14.696 psi, etc.). Accordingly, a negative pressure valueof −X mmHg reflects absolute pressure that is X mmHg below 760 mmHg or,in other words, an absolute pressure of (760−X) mmHg. In addition,negative pressure that is “less” or “smaller” than X mmHg corresponds topressure that is closer to atmospheric pressure (such as, −40 mmHg isless than −60 mmHg). Negative pressure that is “more” or “greater” than−X mmHg corresponds to pressure that is further from atmosphericpressure (such as,−80 mmHg is more than −60 mmHg). In some embodiments,local ambient atmospheric pressure is used as a reference point, andsuch local atmospheric pressure may not necessarily be, for example, 760mmHg.

The negative pressure range for some embodiments of the presentdisclosure can be approximately −80 mmHg, or between about −20 mmHg and−200 mmHg. Note that these pressures are relative to normal ambientatmospheric pressure, which can be 760 mmHg. Thus, −200 mmHg would beabout 560 mmHg in practical terms. In some embodiments, the pressurerange can be between about −40 mmHg and −150 mmHg. Alternatively, apressure range of up to −75 mmHg, up to −80 mmHg or over −80 mmHg can beused. Also in other embodiments a pressure range of below −75 mmHg canbe used. Alternatively, a pressure range of over approximately −100mmHg, or even −150 mmHg, can be supplied by the negative pressureapparatus.

In some embodiments of wound closure devices described herein, increasedwound contraction can lead to increased tissue expansion in thesurrounding wound tissue. This effect may be increased by varying theforce applied to the tissue, for example by varying the negativepressure applied to the wound over time, possibly in conjunction withincreased tensile forces applied to the wound via embodiments of thewound closure devices. In some embodiments, negative pressure may bevaried over time for example using a sinusoidal wave, square wave, or insynchronization with one or more patient physiological indices (such as,heartbeat). Examples of such applications where additional disclosurerelating to the preceding may be found include U.S. Pat. No. 8,235,955,titled “Wound treatment apparatus and method,” issued on Aug. 7, 2012;and U.S. Pat. No. 7,753,894, titled “Wound cleansing apparatus withstress,” issued Jul. 13, 2010. The disclosures of both of these patentsare hereby incorporated by reference in their entirety.

Embodiments of the wound dressings, wound dressing components, woundtreatment apparatuses and methods described herein may also be used incombination or in addition to those described in InternationalApplication No. PCT/IB2013/001469, filed May 22, 2013, published as WO2013/175306 A2 on Nov. 28, 2013, titled “APPARATUSES AND METHODS FORNEGATIVE PRESSURE WOUND THERAPY,” U.S. patent application Ser. No.14/418,908, filed Jan. 30, 2015, published as US 2015/0190286 A1 on Jul.9, 2015, titled “WOUND DRESSING AND METHOD OF TREATMENT,” thedisclosures of which are hereby incorporated by reference in theirentireties. Embodiments of the wound dressings, wound dressingcomponents, wound treatment apparatuses and methods described herein mayalso be used in combination or in addition to those described in U.S.patent application Ser. No. 13/092,042, filed Apr. 21, 2011, publishedas US2011/0282309, titled “WOUND DRESSING AND METHOD OF USE,” and U.S.patent application Ser. No. 14/715,527, filed May 18, 2015, published asUS2016/0339158 A1 on Nov. 24, 2016, titled “FLUIDIC CONNECTOR FORNEGATIVE PRESSURE WOUND THERAPY,” the disclosure of each of which ishereby incorporated by reference in its entirety, including furtherdetails relating to embodiments of wound dressings, the wound dressingcomponents and principles, and the materials used for the wounddressings.

Additionally, some embodiments related to TNP wound treatment comprisinga wound dressing in combination with a pump or associated electronicsdescribed herein may also be used in combination or in addition to thosedescribed in International Application PCT/EP2016/059329 filed Apr. 26,2016, published as WO 2016/174048 on Nov. 3, 2016, entitled “REDUCEDPRESSURE APPARATUS AND METHODS,” the disclosure of which is herebyincorporated by reference in its entirety.

NPWT System Overview

FIG. 1A illustrates an embodiment of a negative or reduced pressurewound treatment (or TNP) system 100 comprising a wound filler 130 placedinside a wound cavity 110, the wound cavity sealed by a wound cover 120.The wound filler 130 in combination with the wound cover 120 can bereferred to as wound dressing. A single or multi lumen tube or conduit140 is connected the wound cover 120 with a pump assembly 150 configuredto supply reduced pressure. The wound cover 120 can be in fluidiccommunication with the wound cavity 110. In any of the systemembodiments disclosed herein, as in the embodiment illustrated in FIG.1, the pump assembly can be a canisterless pump assembly (meaning thatexudate is collected in the wound dressing or is transferred via tube140 for collection to another location). However, any of the pumpassembly embodiments disclosed herein can be configured to include orsupport a canister. Additionally, in any of the system embodimentsdisclosed herein, any of the pump assembly embodiments can be mounted toor supported by the dressing, or adjacent to the dressing.

The wound filler 130 can be any suitable type, such as hydrophilic orhydrophobic foam, gauze, inflatable bag, and so on. The wound filler 130can be conformable to the wound cavity 110 such that it substantiallyfills the cavity. The wound cover 120 can provide a substantially fluidimpermeable seal over the wound cavity 110. The wound cover 120 can havea top side and a bottom side, and the bottom side adhesively (or in anyother suitable manner) seals with wound cavity 110. The conduit 140 orlumen or any other conduit or lumen disclosed herein can be formed frompolyurethane, PVC, nylon, polyethylene, silicone, or any other suitablematerial.

Some embodiments of the wound cover 120 can have a port (not shown)configured to receive an end of the conduit 140. For example, the portcan be Renasys Soft Port available from Smith & Nephew. In otherembodiments, the conduit 140 can otherwise pass through or under thewound cover 120 to supply reduced pressure to the wound cavity 110 so asto maintain a desired level of reduced pressure in the wound cavity. Theconduit 140 can be any suitable article configured to provide at least asubstantially sealed fluid flow pathway between the pump assembly 150and the wound cover 120, so as to supply the reduced pressure providedby the pump assembly 150 to wound cavity 110.

The wound cover 120 and the wound filler 130 can be provided as a singlearticle or an integrated single unit. In some embodiments, no woundfiller is provided and the wound cover by itself may be considered thewound dressing. The wound dressing may then be connected, via theconduit 140, to a source of negative pressure, such as the pump assembly150. The pump assembly 150 can be miniaturized and portable, althoughlarger conventional pumps such can also be used.

The wound cover 120 can be located over a wound site to be treated. Thewound cover 120 can form a substantially sealed cavity or enclosure overthe wound site. In some embodiments, the wound cover 120 can beconfigured to have a film having a high water vapour permeability toenable the evaporation of surplus fluid, and can have a superabsorbingmaterial contained therein to safely absorb wound exudate. It will beappreciated that throughout this specification reference is made to awound. In this sense it is to be understood that the term wound is to bebroadly construed and encompasses open and closed wounds in which skinis torn, cut or punctured or where trauma causes a contusion, or anyother surficial or other conditions or imperfections on the skin of apatient or otherwise that benefit from reduced pressure treatment. Awound is thus broadly defined as any damaged region of tissue wherefluid may or may not be produced. Examples of such wounds include, butare not limited to, acute wounds, chronic wounds, surgical incisions andother incisions, subacute and dehisced wounds, traumatic wounds, flapsand skin grafts, lacerations, abrasions, contusions, burns, diabeticulcers, pressure ulcers, stoma, surgical wounds, trauma and venousulcers or the like. The components of the TNP system described hereincan be particularly suited for incisional wounds that exude a smallamount of wound exudate.

Some embodiments of the system are designed to operate without the useof an exudate canister. Some embodiments can be configured to support anexudate canister. In some embodiments, configuring the pump assembly 150and tubing 140 so that the tubing 140 can be quickly and easily removedfrom the pump assembly 150 can facilitate or improve the process ofdressing or pump changes, if necessary. Any of the pump embodimentsdisclosed herein can be configured to have any suitable connectionbetween the tubing and the pump.

The pump assembly 150 can be configured to deliver negative pressure ofapproximately −80 mmHg, or between about −20 mmHg and 200 mmHg in someimplementations. Note that these pressures are relative to normalambient atmospheric pressure thus, −200 mmHg would be about 560 mmHg inpractical terms. The pressure range can be between about −40 mmHg and−150 mmHg. Alternatively, a pressure range of up to −75 mmHg, up to −80mmHg or over −80 mmHg can be used. Also, a pressure range of below −75mmHg can be used. Alternatively, a pressure range of over approximately−100 mmHg, or even 150 mmHg, can be supplied by the pump assembly 150.

In operation, the wound filler 130 is inserted into the wound cavity 110and wound cover 120 is placed so as to seal the wound cavity 110. Thepump assembly 150 provides a source of a negative pressure to the woundcover 120, which is transmitted to the wound cavity 110 via the woundfiller 130. Fluid (such as, wound exudate) is drawn through the conduit140, and can be stored in a canister. In some embodiments, fluid isabsorbed by the wound filler 130 or one or more absorbent layers (notshown).

Wound dressings that may be utilized with the pump assembly and otherembodiments of the present application include Renasys-F, Renasys-G,Renasys AB, and Pico Dressings available from Smith & Nephew. Furtherdescription of such wound dressings and other components of a negativepressure wound therapy system that may be used with the pump assemblyand other embodiments of the present application are found in U.S.Patent Publication Nos. 2011/0213287, 2011/0282309, 2012/0116334,2012/0136325, and 2013/0110058, which are incorporated by reference intheir entirety. In other embodiments, other suitable wound dressings canbe utilized.

Wound Dressing Overview FIG. 1B illustrates a cross-section through awound dressing 155 according to some embodiments. FIG. 1B alsoillustrates a fluidic connector 160 according to some embodiments. Thewound dressing 155 can be similar to the wound dressing described inInternational Patent Publication WO2013175306 A2, which is incorporatedby reference in its entirety. Alternatively, the wound dressing 155 canbe any wound dressing embodiment disclosed herein or any combination offeatures of any number of wound dressing embodiments disclosed herein,can be located over a wound site to be treated. The wound dressing 155may be placed as to form a sealed cavity over the wound, such as thewound cavity 110. In some embodiments, the wound dressing 155 includes atop or cover layer, or backing layer 220 attached to an optional woundcontact layer 222, both of which are described in greater detail below.These two layers 220, 222 can be joined or sealed together so as todefine an interior space or chamber. This interior space or chamber maycomprise additional structures that may be adapted to distribute ortransmit negative pressure, store wound exudate and other fluids removedfrom the wound, and other functions which will be explained in greaterdetail below. Examples of such structures, described below, include atransmission layer 226 and an absorbent layer 221.

As used herein the upper layer, top layer, or layer above refers to alayer furthest from the surface of the skin or wound while the dressingis in use and positioned over the wound. Accordingly, the lower surface,lower layer, bottom layer, or layer below refers to the layer that isclosest to the surface of the skin or wound while the dressing is in useand positioned over the wound.

The wound contact layer 222 can be a polyurethane layer or polyethylenelayer or other flexible layer which is perforated, for example via a hotpin process, laser ablation process, ultrasound process or in some otherway or otherwise made permeable to liquid and gas. The wound contactlayer 222 has a lower surface 224 (for example, facing the wound) and anupper surface 223 (for example, facing away from the wound). Theperforations 225 can comprise through holes in the wound contact layer222 which enable fluid to flow through the layer 222. The wound contactlayer 222 helps prevent tissue ingrowth into the other material of thewound dressing. In some embodiments, the perforations are small enoughto meet this requirement while still allowing fluid to flowtherethrough. For example, perforations formed as slits or holes havinga size ranging from 0.025 mm to 1.2 mm are considered small enough tohelp prevent tissue ingrowth into the wound dressing while allowingwound exudate to flow into the dressing. In some configurations, thewound contact layer 222 may help maintain the integrity of the entiredressing 155 while also creating an air tight seal around the absorbentpad in order to maintain negative pressure at the wound. In someembodiments, the wound contact layer is configured to allowunidirectional or substantially one-way or unidirectional flow of fluidthrough the wound contact layer when negative pressure is applied to thewound. For example, the wound contact layer can permit fluid to flowaway from the wound through the wound contact layer, but not allow fluidto flow back toward the wound. In certain case, the perforations in thewound contact layer are configured to permit such one-way orunidirectional flow of fluid through the wound contact layer.

Some embodiments of the wound contact layer 222 may also act as acarrier for an optional lower and upper adhesive layer (not shown). Forexample, a lower pressure sensitive adhesive may be provided on thelower surface 224 of the wound dressing 155 whilst an upper pressuresensitive adhesive layer may be provided on the upper surface 223 of thewound contact layer. The pressure sensitive adhesive, which may be asilicone, hot melt, hydrocolloid or acrylic based adhesive or other suchadhesives, may be formed on both sides or optionally on a selected oneor none of the sides of the wound contact layer. When a lower pressuresensitive adhesive layer is utilized may be helpful to adhere the wounddressing 155 to the skin around a wound site. In some embodiments, thewound contact layer may comprise perforated polyurethane film. The lowersurface of the film may be provided with a silicone pressure sensitiveadhesive and the upper surface may be provided with an acrylic pressuresensitive adhesive, which may help the dressing maintain its integrity.In some embodiments, a polyurethane film layer may be provided with anadhesive layer on both its upper surface and lower surface, and allthree layers may be perforated together.

A layer 226 of porous material can be located above the wound contactlayer 222. This porous layer, or transmission layer, 226 allowstransmission of fluid including liquid and gas away from a wound siteinto upper layers of the wound dressing. In particular, the transmissionlayer 226 can ensure that an open air channel can be maintained tocommunicate negative pressure over the wound area even when theabsorbent layer has absorbed substantial amounts of exudates. The layer226 can remain open under the typical pressures that will be appliedduring negative pressure wound therapy as described above, so that thewhole wound site sees an equalized negative pressure. The layer 226 maybe formed of a material having a three-dimensional structure. Forexample, a knitted or woven spacer fabric (for example Baltex 7970 weftknitted polyester) or a non-woven fabric could be used.

In some embodiments, the transmission layer 226 comprises a 3D polyesterspacer fabric layer including a top layer (that is to say, a layerdistal from the wound-bed in use) which is a 84/144 textured polyester,and a bottom layer (that is to say, a layer which lies proximate to thewound bed in use) which is a 10 denier flat polyester and a third layerformed sandwiched between these two layers which is a region defined bya knitted polyester viscose, cellulose or the like monofilament fiber.Other materials and other linear mass densities of fiber could of coursebe used.

Whilst reference is made throughout this disclosure to a monofilamentfiber it will be appreciated that a multistrand alternative could ofcourse be utilized. The top spacer fabric thus has more filaments in ayarn used to form it than the number of filaments making up the yarnused to form the bottom spacer fabric layer.

This differential between filament counts in the spaced apart layershelps control moisture flow across the transmission layer. Particularly,by having a filament count greater in the top layer, that is to say, thetop layer is made from a yarn having more filaments than the yarn usedin the bottom layer, liquid tends to be wicked along the top layer morethan the bottom layer. In use, this differential tends to draw liquidaway from the wound bed and into a central region of the dressing wherethe absorbent layer 221 helps lock the liquid away or itself wicks theliquid onwards towards the cover layer where it can be transpired.

In some embodiments, to improve the liquid flow across the transmissionlayer 226 (that is to say perpendicular to the channel region formedbetween the top and bottom spacer layers) the 3D fabric may be treatedwith a dry cleaning agent (such as, but not limited to, PerchloroEthylene) to help remove any manufacturing products such as mineraloils, fats or waxes used previously which might interfere with thehydrophilic capabilities of the transmission layer. An additionalmanufacturing step can subsequently be carried in which the 3D spacerfabric is washed in a hydrophilic agent (such as, but not limited to,Feran Ice 30 g/I available from the Rudolph Group). This process stephelps ensure that the surface tension on the materials is so low thatliquid such as water can enter the fabric as soon as it contacts the 3Dknit fabric. This also aids in controlling the flow of the liquid insultcomponent of any exudates.

A layer 221 of absorbent material can be provided above the transmissionlayer 226. The absorbent material, which comprise a foam or non-wovennatural or synthetic material, and which may optionally comprise asuper-absorbent material, forms a reservoir for fluid, particularlyliquid, removed from the wound site. In some embodiments, the layer 221may also aid in drawing fluids towards the backing layer 220.

The material of the absorbent layer 221 may also prevent liquidcollected in the wound dressing 155 from flowing freely within thedressing, and can act so as to contain any liquid collected within thedressing. The absorbent layer 221 also helps distribute fluid throughoutthe layer via a wicking action so that fluid is drawn from the woundsite and stored throughout the absorbent layer. This helps preventagglomeration in areas of the absorbent layer. The capacity of theabsorbent material must be sufficient to manage the exudates flow rateof a wound when negative pressure is applied. Since in use the absorbentlayer experiences negative pressures the material of the absorbent layeris chosen to absorb liquid under such circumstances. A number ofmaterials exist that are able to absorb liquid when under negativepressure, for example superabsorber material. The absorbent layer 221may typically be manufactured from ALLEVYN™ foam, Freudenberg 114-224-4or Chem-Posite™ 11C-450. In some embodiments, the absorbent layer 221may comprise a composite comprising superabsorbent powder, fibrousmaterial such as cellulose, and bonding fibers. In some embodiments, thecomposite is an airlaid, thermally-bonded composite.

In some embodiments, the absorbent layer 221 is a layer of non-wovencellulose fibers having super-absorbent material in the form of dryparticles dispersed throughout. Use of the cellulose fibers introducesfast wicking elements which help quickly and evenly distribute liquidtaken up by the dressing. The juxtaposition of multiple strand-likefibers leads to strong capillary action in the fibrous pad which helpsdistribute liquid. In this way, the super-absorbent material isefficiently supplied with liquid. The wicking action also assists inbringing liquid into contact with the upper cover layer to aid increasetranspiration rates of the dressing.

An aperture, hole, or orifice 227 can be provided in the backing layer220 to allow a negative pressure to be applied to the dressing 155. Insome embodiments, the fluidic connector 160 is attached or sealed to thetop of the backing layer 220 over the orifice 227 made into the dressing155, and communicates negative pressure through the orifice 227. Alength of tubing may be coupled at a first end to the fluidic connector160 and at a second end to a pump unit (not shown) to allow fluids to bepumped out of the dressing. Where the fluidic connector is adhered tothe top layer of the wound dressing, a length of tubing may be coupledat a first end of the fluidic connector such that the tubing, orconduit, extends away from the fluidic connector parallel orsubstantially to the top surface of the dressing. The fluidic connector160 may be adhered and sealed to the backing layer 220 using an adhesivesuch as an acrylic, cyanoacrylate, epoxy, UV curable or hot meltadhesive. The fluidic connector 160 may be formed from a soft polymer,for example a polyethylene, a polyvinyl chloride, a silicone orpolyurethane having a hardness of 30 to 90 on the Shore A scale. In someembodiments, the fluidic connector 160 may be made from a soft orconformable material.

In some embodiments, the absorbent layer 221 includes at least onethrough hole 228 located so as to underlie the fluidic connector 160.The through hole 228 may in some embodiments be the same size as theopening 227 in the backing layer, or may be bigger or smaller. Asillustrated in FIG. 1B a single through hole can be used to produce anopening underlying the fluidic connector 160. It will be appreciatedthat multiple openings could alternatively be utilized. Additionally,should more than one port be utilized according to certain embodimentsof the present disclosure one or multiple openings may be made in theabsorbent layer and the obscuring layer in registration with eachrespective fluidic connector. Although not essential to certainembodiments of the present disclosure the use of through holes in thesuper-absorbent layer may provide a fluid flow pathway which remainsunblocked in particular when the absorbent layer is near saturation.

The aperture or through-hole 228 can be provided in the absorbent layer221 beneath the orifice 227 such that the orifice is connected directlyto the transmission layer 226 as illustrated in FIG. 1B. This allows thenegative pressure applied to the fluidic connector 160 to becommunicated to the transmission layer 226 without passing through theabsorbent layer 221. This ensures that the negative pressure applied tothe wound site is not inhibited by the absorbent layer as it absorbswound exudates. In other embodiments, no aperture may be provided in theabsorbent layer 221, or alternatively a plurality of aperturesunderlying the orifice 227 may be provided. In further alternativeembodiments, additional layers such as another transmission layer or anobscuring layer such as described in International Patent PublicationWO2014020440, the entirety of which is hereby incorporated by reference,may be provided over the absorbent layer 221 and beneath the backinglayer 220.

The backing layer 220 is can be gas impermeable, but moisture vaporpermeable, and can extend across the width of the wound dressing 155.The backing layer 220, which may for example be a polyurethane film (forexample, Elastollan SP9109) having a pressure sensitive adhesive on oneside, is impermeable to gas and this layer thus operates to cover thewound and to seal a wound cavity over which the wound dressing isplaced. In this way an effective chamber is made between the backinglayer 220 and a wound site where a negative pressure can be established.The backing layer 220 can be sealed to the wound contact layer 222 in aborder region around the circumference of the dressing, ensuring that noair is drawn in through the border area, for example via adhesive orwelding techniques. The backing layer 220 protects the wound fromexternal bacterial contamination (bacterial barrier) and allows liquidfrom wound exudates to be transferred through the layer and evaporatedfrom the film outer surface. The backing layer 220 can include twolayers; a polyurethane film and an adhesive pattern spread onto thefilm. The polyurethane film can be moisture vapor permeable and may bemanufactured from a material that has an increased water transmissionrate when wet. In some embodiments the moisture vapor permeability ofthe backing layer increases when the backing layer becomes wet. Themoisture vapor permeability of the wet backing layer may be up to aboutten times more than the moisture vapor permeability of the dry backinglayer.

The absorbent layer 221 may be of a greater area than the transmissionlayer 226, such that the absorbent layer overlaps the edges of thetransmission layer 226, thereby ensuring that the transmission layerdoes not contact the backing layer 220. This provides an outer channelof the absorbent layer 221 that is in direct contact with the woundcontact layer 222, which aids more rapid absorption of exudates to theabsorbent layer. Furthermore, this outer channel ensures that no liquidis able to pool around the circumference of the wound cavity, which mayotherwise seep through the seal around the perimeter of the dressingleading to the formation of leaks. As illustrated in FIG. 1B, theabsorbent layer 221 may define a smaller perimeter than that of thebacking layer 220, such that a boundary or border region is definedbetween the edge of the absorbent layer 221 and the edge of the backinglayer 220.

As shown in FIG. 1B, one embodiment of the wound dressing 155 comprisesan aperture 228 in the absorbent layer 221 situated underneath thefluidic connector 160. In use, for example when negative pressure isapplied to the dressing 155, a wound facing portion of the fluidicconnector may thus come into contact with the transmission layer 226,which can thus aid in transmitting negative pressure to the wound siteeven when the absorbent layer 221 is filled with wound fluids. Someembodiments may have the backing layer 220 be at least partly adhered tothe transmission layer 226. In some embodiments, the aperture 228 is atleast 1-2 mm larger than the diameter of the wound facing portion of thefluidic connector 11, or the orifice 227.

For example, in embodiments with a single fluidic connector 160 andthrough hole, it may be preferable for the fluidic connector 160 andthrough hole to be located in an off-center position. Such a locationmay permit the dressing 155 to be positioned onto a patient such thatthe fluidic connector 160 is raised in relation to the remainder of thedressing 155. So positioned, the fluidic connector 160 and the filter214 may be less likely to come into contact with wound fluids that couldprematurely occlude the filter 214 so as to impair the transmission ofnegative pressure to the wound site.

Turning now to the fluidic connector 160, some embodiments include asealing surface 216, a bridge 211 with a proximal end (closer to thenegative pressure source) and a distal end 140, and a filter 214. Thesealing surface 216 can form the applicator that is sealed to the topsurface of the wound dressing. In some embodiments a bottom layer of thefluidic connector 160 may comprise the sealing surface 216. The fluidicconnector 160 may further comprise an upper surface vertically spacedfrom the sealing surface 216, which in some embodiments is defined by aseparate upper layer of the fluidic connector. In other embodiments theupper surface and the lower surface may be formed from the same piece ofmaterial. In some embodiments the sealing surface 216 may comprise atleast one aperture 229 therein to communicate with the wound dressing.In some embodiments the filter 214 may be positioned across the opening229 in the sealing surface, and may span the entire opening 229. Thesealing surface 216 may be configured for sealing the fluidic connectorto the cover layer of the wound dressing, and may comprise an adhesiveor weld. In some embodiments, the sealing surface 216 may be placed overan orifice in the cover layer with optional spacer elements 215configured to create a gap between the filter 214 and the transmissionlayer 226. In other embodiments, the sealing surface 216 may bepositioned over an orifice in the cover layer and an aperture in theabsorbent layer 220, permitting the fluidic connector 160 to provide airflow through the transmission layer 226. In some embodiments, the bridge211 may comprise a first fluid passage 212 in communication with asource of negative pressure, the first fluid passage 212 comprising aporous material, such as a 3D knitted material, which may be the same ordifferent than the porous layer 226 described previously. The bridge 211can be encapsulated by at least one flexible film layer 208, 210 havinga proximal and distal end and configured to surround the first fluidpassage 212, the distal end of the flexible film being connected to thesealing surface 216. The filter 214 is configured to substantiallyprevent wound exudate from entering the bridge, and spacer elements 215are configured to prevent the fluidic connector from contacting thetransmission layer 226. These elements will be described in greaterdetail below.

Some embodiments may further comprise an optional second fluid passagepositioned above the first fluid passage 212. For example, someembodiments may provide for an air leak may be disposed at the proximalend of the top layer that is configured to provide an air path into thefirst fluid passage 212 and dressing 155 similar to the suction adapteras described in U.S. Pat. No. 8,801,685, which is incorporated byreference herein in its entirety.

In some embodiment, the fluid passage 212 is constructed from acompliant material that is flexible and that also permits fluid to passthrough it if the spacer is kinked or folded over. Suitable materialsfor the fluid passage 212 include without limitation foams, includingopen-cell foams such as polyethylene or polyurethane foam, meshes, 3Dknitted fabrics, non-woven materials, and fluid channels. In someembodiments, the fluid passage 212 may be constructed from materialssimilar to those described above in relation to the transmission layer226. Advantageously, such materials used in the fluid passage 212 notonly permit greater patient comfort, but may also provide greater kinkresistance, such that the fluid passage 212 is still able to transferfluid from the wound toward the source of negative pressure while beingkinked or bent.

In some embodiments, the fluid passage 212 may be comprised of a wickingfabric, for example a knitted or woven spacer fabric (such as a knittedpolyester 3D fabric, Baltex 7970®, or Gehring 879®) or a nonwovenfabric. These materials selected can be suited to channeling woundexudate away from the wound and for transmitting negative pressure orvented air to the wound site, and may also confer a degree of kinking orocclusion resistance to the fluid passage 212. In some embodiments, thewicking fabric may have a three-dimensional structure, which in somecases may aid in wicking fluid or transmitting negative pressure. Incertain embodiments, including wicking fabrics, these materials remainopen and capable of communicating negative pressure to a wound areaunder the typical pressures used in negative pressure therapy, forexample between −40 to −150 mmHg. In some embodiments, the wickingfabric may comprise several layers of material stacked or layered overeach other, which may in some cases be useful in preventing the fluidpassage 212 from collapsing under the application of negative pressure.In other embodiments, the wicking fabric used in the fluid passage 212may be between 1.5 mm and 6 mm; more preferably, the wicking fabric maybe between 3 mm and 6 mm thick, and may be comprised of either one orseveral individual layers of wicking fabric. In other embodiments, thefluid passage 212 may be between 1.2-3 mm thick, and preferably thickerthan 1.5 mm. Some embodiments, for example a suction adapter used with adressing which retains liquid such as wound exudate, may employhydrophobic layers in the fluid passage 212, and only gases may travelthrough the fluid passage 212. Additionally, and as describedpreviously, the materials used in the system can be conformable andsoft, which may help to avoid pressure ulcers and other complicationswhich may result from a wound treatment system being pressed against theskin of a patient.

In some embodiments, the filter element 214 is impermeable to liquids,but permeable to gases, and is provided to act as a liquid barrier andto ensure that no liquids are able to escape from the wound dressing155. The filter element 214 may also function as a bacterial barrier.Typically, the pore size is 0.2 μm. Suitable materials for the filtermaterial of the filter element 214 include 0.2 micron Gore™ expandedPTFE from the MMT range, PALL Versapore™ 200R, and Donaldson™ TX6628.Larger pore sizes can also be used but these may require a secondaryfilter layer to ensure full bioburden containment. As wound fluidcontains lipids it is preferable, though not essential, to use anoleophobic filter membrane for example 1.0 micron MMT-332 prior to 0.2micron MMT-323. This prevents the lipids from blocking the hydrophobicfilter. The filter element can be attached or sealed to the port or thecover film over the orifice. For example, the filter element 214 may bemolded into the fluidic connector 160, or may be adhered to one or bothof the top of the cover layer and bottom of the suction adapter 160using an adhesive such as, but not limited to, a UV cured adhesive.

It will be understood that other types of material could be used for thefilter element 214. More generally a microporous membrane can be usedwhich is a thin, flat sheet of polymeric material, this containsbillions of microscopic pores. Depending upon the membrane chosen thesepores can range in size from 0.01 to more than 10 micrometers.Microporous membranes are available in both hydrophilic (waterfiltering) and hydrophobic (water repellent) forms. In some embodiments,filter element 214 comprises a support layer and an acrylic copolymermembrane formed on the support layer. In some embodiments, the wounddressing 155 according to certain embodiments uses microporoushydrophobic membranes (MHMs). Numerous polymers may be employed to formMHMs. For example, the MHMs may be formed from one or more of PTFE,polypropylene, PVDF and acrylic copolymer. All of these optionalpolymers can be treated in order to obtain specific surfacecharacteristics that can be both hydrophobic and oleophobic. As suchthese will repel liquids with low surface tensions such as multi-vitamininfusions, lipids, surfactants, oils and organic solvents.

MHMs block liquids whilst allowing air to flow through the membranes.They are also highly efficient air filters eliminating potentiallyinfectious aerosols and particles. A single piece of MHM is well knownas an option to replace mechanical valves or vents. Incorporation ofMHMs can thus reduce product assembly costs improving profits andcosts/benefit ratio to a patient.

The filter element 214 may also include an odor absorbent material, forexample activated charcoal, carbon fiber cloth or Vitec Carbotec-RTQ2003073 foam, or the like. For example, an odor absorbent material mayform a layer of the filter element 214 or may be sandwiched betweenmicroporous hydrophobic membranes within the filter element. The filterelement 214 thus enables gas to be exhausted through the orifice.Liquid, particulates and pathogens however are contained in thedressing.

The wound dressing 155 may comprise spacer elements 215 in conjunctionwith the fluidic connector 160 and the filter 214. With the addition ofsuch spacer elements 215 the fluidic connector 160 and filter 214 may besupported out of direct contact with the absorbent layer 220 or thetransmission layer 226. The absorbent layer 220 may also act as anadditional spacer element to keep the filter 214 from contacting thetransmission layer 226. Accordingly, with such a configuration contactof the filter 214 with the transmission layer 226 and wound fluidsduring use may thus be minimized.

Similar to the embodiments of wound dressings described above, somewound dressings comprise a perforated wound contact layer with siliconeadhesive on the skin-contact face and acrylic adhesive on the reverse.Above this bordered layer sits a transmission layer or a 3D spacerfabric pad. Above the transmission layer, sits an absorbent layer. Theabsorbent layer can include a superabsorbent non-woven (NW) pad. Theabsorbent layer can over-border the transmission layer by approximately5 mm at the perimeter. The absorbent layer can have an aperture orthrough-hole toward one end. The aperture can be about 10 mm indiameter. Over the transmission layer and absorbent layer lies a backinglayer. The backing layer can be a high moisture vapor transmission rate(MVTR) film, pattern coated with acrylic adhesive. The high MVTR filmand wound contact layer encapsulate the transmission layer and absorbentlayer, creating a perimeter border of approximately 20 mm. The backinglayer can have a 10 mm aperture that overlies the aperture in theabsorbent layer. Above the hole can be bonded a fluidic connector thatcomprises a liquid-impermeable, gas-permeable semi-permeable membrane(SPM) or filter that overlies the aforementioned apertures.

Wound Dressing with Sensors

A wound dressing that incorporates a number of sensors can be utilizedin order to monitor characteristics of a wound as it heals. Collectingdata from the wounds that heal well, and from those that do not, canprovide useful insights towards identifying measurands to indicatewhether a wound is on a healing trajectory.

In some implementations, a number of sensor technologies can be used inwound dressings or one or more components forming part of an overallwound dressing apparatus. For example, as illustrated in FIGS. 2 and 3D,which depict wound dressings 250 and 320 with sensor arrays according tosome embodiments, one or more sensors can be incorporated onto or into awound contact layer, which may be a perforated wound contact layer asshown in FIG. 3D. The wound contact layer in FIGS. 2 and 3D isillustrated as having a square shape, but it will be appreciated thatthe wound contact layer may have other shapes such as rectangular,circular, oval, etc. In some embodiments, the sensor integrated woundcontact layer can be provided as an individual material layer that isplaced over the wound area and then covered by a wound dressingapparatus or components of a wound dressing apparatus, such as gauze,foam or other wound packing material, a superabsorbent layer, a drape, afully integrated dressing like the Pico or Allevyn Life dressing, etc.In other embodiments, the sensor integrated wound contact layer may bepart of a single unit dressing such as described herein.

The sensor-integrated wound contact layer can be placed in contact withthe wound and will allow fluid to pass through the contact layer whilecausing little to no damage to the tissue in the wound. Thesensor-integrated wound contact layer can be made of a flexible materialsuch as silicone and can incorporate antimicrobials or other therapeuticagents known in the art. In some embodiments, the sensor-integratedwound contact layer can incorporate adhesives that adhere to wet or drytissue. In some embodiments, the sensors or sensor array can beincorporated into or encapsulated within other components of the wounddressing such as the absorbent layer or spacer layer described above.

As shown in FIGS. 2 and 3D, five sensors can be used, including, forinstance, sensors for temperature (such as, 25 thermistor sensors, in a5×5 array, 20 mm pitch), oxygen saturation or SpO2 (such as, 4 or 5 SpO2sensors, in a single line from the center of the wound contact layer tothe edge thereof, 10 mm pitch), tissue color (such as, 10 opticalsensors, in 2×5 array, ˜20 mm pitch; not all 5 sensors in each row ofthe array need be aligned), pH (such as, by measuring colour of a pHsensitive pad, optionally using the same optical sensors as for tissuecolour), and conductivity (such as, 9 conductivity contacts, in a 3×3array, ˜40 mm pitch). As shown in FIG. 3A, the SpO2 sensors can bearranged in a single line from the center of or near the center of thewound contact layer to the edge of the wound contact layer. The line ofSpO2 sensors can allow the sensor to take measurements in the middle ofthe wound, at the edge or the wound, or on intact skin to measurechanges between the various regions. In some embodiments, the woundcontact layer or sensor array can be larger than the size of the woundto cover the entire surface area of the wound as well as the surroundingintact skin. The larger size of the wound contact layer and/or sensorarray and the multiple sensors can provide more information about thewound area than if the sensor was only placed in the center of the woundor in only one area at a time.

The sensors can be incorporated onto flexible circuit boards formed offlexible polymers including polyamide, polyimide (PI), polyester,polyethylene naphthalate (PEN), polyetherimide (PEI), along with variousfluropolymers (FEP) and copolymers, or any material known in the art.The sensor array can be incorporated into a two-layer flexible circuit.In some embodiments, the circuit board can be a multi-layer flexiblecircuit board. In some embodiments, these flexible circuits can beincorporated into any layer of the wound dressing. In some embodiments,a flexible circuit can be incorporated into a wound contact layer. Forexample, the flexible circuit can be incorporated into a wound contactlayer similar to the wound contact layer described with reference toFIG. 1B. The wound contact layer can have cutouts or slits that allowfor one or more sensors to protrude out of the lower surface of thewound contact layer and contact the wound area directly.

In some embodiments, the sensor-integrated wound contact layer caninclude a first and second wound contact layer with the flexible circuitboard sandwiched between the two layers of wound contact layer material.The first wound contact layer has a lower surface intended to be incontact with the wound and an upper surface intended to be in contactwith flexible circuit board. The second wound contact layer has a lowersurface intended to be in contact with the flexible circuit board and anupper surface intended to be in contact with a wound dressing or one ormore components forming part of an overall wound dressing apparatus. Theupper surface of the first wound contact layer and the lower surface ofthe second wound contact layer can be adhered together with the flexiblecircuit board sandwiched between the two layers.

In some embodiments, the one or more sensors of the flexible circuitboard can be fully encapsulated or covered by the wound contact layersto prevent contact with moisture or fluid in the wound. In someembodiments, the first wound contact layer can have cutouts or slitsthat allow for one or more sensors to protrude out of the lower surfaceand contact the wound area directly. For example, the one or more SpO2sensors as shown in FIG. 3D are shown protruding out the bottom surfaceof the wound contact layer. In some embodiments, the SpO2 sensors can bemounted directly on a lower surface of the first wound contact layer.Some or all of the sensors and electrical or electronic components maybe potted or encapsulated (for example, rendered waterproof orliquid-proof) with a polymer, for example, silicon or epoxy basedpolymers. The encapsulation with a polymer can prevent ingress of fluidand leaching of chemicals from the components. In some embodiments, thewound contact layer material can seal the components from water ingressand leaching of chemicals.

In some embodiments, gathering and processing information related to thewound can utilize three components, including a sensor array, a controlor processing module, and software. These components are described inmore detail herein.

FIG. 3A illustrates a flexible sensor array circuit board 300 thatincludes a sensor array portion 301, a tail portion 302, and a connectorpad end portion 303 according to some embodiments. The sensor arrayportion 301 can include the sensors and associated circuitry. The sensorarray circuit board 300 can include a long tail portion 302 extendingfrom the sensor array portion 301. The connector pad end portion 303 canbe enabled to connect to a control module or other processing unit toreceive the data from the sensor array circuit. The long tail portion302 can allow the control module to be placed distant from the wound,such as for example in a more convenient location away from the wound.

FIG. 3B illustrates embodiments of the flexible circuit boards with fourdifferent sensor array geometries 301A, 301B, 301C, and 301D accordingto some embodiments. The illustrated embodiments include tail portions302A, 302B. 302C, and 302D. In some embodiments, four different sensorarray geometries shown can be implemented in flexible circuits. WhileFIG. 3B show four different sensor array formats and configurations, thedesign 301B and 302B also includes the connector pads end portion 303configured to provide electrical or electronic connection between thesponsor array 301B and a control module. One or more of the designs in301A, 301C, or 301D can also include a connector pads end portion, suchas the portion 303, to allow flexible circuit boards 301A, 301C, or 301Dto communicate with a control module or other processing unit. In someembodiments, the sensor array communicates with the control modulewirelessly and the tail portion may be omitted.

FIG. 3C shows the sensor array portion 301B of the sensor array designshown of FIG. 3B in more detail. In any one or more of the embodimentsof FIG. 2 or 3A-3D, the sensor array portion can include a plurality ofportions that extend either around a perimeter of a wound dressingcomponent such as a wound contact layer, or inward from an outer edge ofthe wound dressing component. For example, the illustrated embodimentsinclude a plurality of linearly extending portions that may be parallelto edges of a wound dressing component, and in some embodiments, followthe entire perimeter of the wound dressing component. In someembodiments, the sensor array portion may comprise a first plurality ofparallel linearly extending portions that are perpendicular to a secondplurality of parallel linearly extending portions. These linearlyextending portions may also have different lengths and may extend inwardto different locations within an interior of a wound dressing component.The sensor array portion preferably does not cover the entire wounddressing component, so that gaps are formed between portions of thesensor array. As shown in FIG. 2, this allows some, and possibly amajority of the wound dressing component to be uncovered by the sensorarray. For example, for a perforated wound contact layer as shown inFIGS. 2 and 3D, the sensor array portion 301 may not block a majority ofthe perforations in the wound contact layer. In some embodiments, thesensor array may also be perforated or shaped to match the perforationsin the wound contact layer to minimize the blocking of perforations tofluid flow.

FIG. 3D illustrates a flexible sensor array incorporated into aperforated wound contact layer 320 according to some embodiments. As isillustrated, the sensor array can be sandwiched between two films orwound contact layers. The wound contact layers can have perforationsformed as slits or holes as described herein that are small enough tohelp prevent tissue ingrowth into the wound dressing while allowingwound exudate to flow into the dressing. In some embodiments, the woundcontact layers can have one or more slits that increase flexibility ofthe wound contact layer with integrated sensor array. In someembodiments, one of the wound contact layers can have extra cut outs toaccommodate the sensors so that they can contact the skin directly.

Connectivity for the sensor array can vary depending on the varioussensors and sensor array designs utilized. In some embodiments, forexample as shown in FIG. 3B, a total of 79 connections can be used toconnect the components of the sensor array. The sensor arrays can beterminated in two parallel 40-way 0.5 mm pitch Flat Flexible Cable (FFC)contact surfaces, with terminals on the top surface, designed to beconnected to an FFC connector such as Molex 54104-4031.

In some embodiments, one or more of thermistors, conductivity sensors,SpO2 sensors, or color sensors can be used on the sensor array toprovide information relating to conditions of the wound. The sensorarray and individual sensors can assist a clinician in monitoring thehealing of the wound. The one or more sensors can operate individuallyor in coordination with each other to provide data relating to the woundand wound healing characteristics.

Temperature sensors can use thermocouples or thermistors to measuretemperature. The thermistors can be used to measure or track thetemperature of the underlying wound or the thermal environment withinthe wound dressing. The thermometry sensors can be calibrated and thedata obtained from the sensors can be processed to provide informationabout the wound environment. In some embodiments, an ambient sensormeasuring ambient air temperature can also be used to assist ineliminating problems associated with environment temperature shifts.

Optical sensors can be used to measure wound appearance using an RGBsensor with an illumination source. In some embodiments, both the RGBsensor and the illumination source would be pressed up against the skin,such that light would penetrate into the tissue and take on the spectralfeatures of the tissue itself.

Light propagation in tissue can be dominated by two major phenomena,scattering and attenuation. For attenuation, as light passes throughtissue, its intensity may be lost due to absorption by variouscomponents of the tissue. Blue light tends to be attenuated heavily,whilst light at the red end of the spectrum tends to be attenuatedleast.

Scattering processes can be more complex, and can have various “regimes”which must be considered. The first aspect of scattering is based on thesize of the scattering centre compared with the wavelength of incidentlight. If the scattering center is much smaller than the wavelength oflight, then Rayleigh scattering can be assumed. If the scattering centeris on the order of the wavelength of light, then a more detailed Miescattering formulation must be considered. Another factor involved inscattering light is the distance between input and output of thescattering media. If the mean free path of the light (the distancebetween scattering events) is much larger than the distance travelled,then ballistic photon transport is assumed. In the case of tissue,scatting events are approximately 100 microns apart—so a 1 mm pathdistance would effectively randomise the photon direction and the systemwould enter a diffusive regime.

Ultra bright light emitting diodes (LEDs), an RGB sensor, and polyesteroptical filters can be used as components of the optical sensors tomeasure through tissue color differentiation. For example, becausesurface color can be measured from reflected light, a color can bemeasured from light which has passed through the tissue first for agiven geometry. This can include color sensing from diffuse scatteredlight, from an LED in contact with the skin. In some embodiments, an LEDcan be used with an RGB sensor nearby to detect the light which hasdiffused through the tissue. The optical sensors can image with diffuseinternal light or surface reflected light.

Additionally, the optical sensors can be used to measureautofluorescence. Autofluorescence is used because the tissue isabsorbing light at one wavelength, and emitting at another.Additionally, dead tissue may not auto-fluoresce and so this could be avery strong indication as to if the tissue is healthy or not. Due toblue light (or even UV light) having such a short penetration depth, itmay be very useful for example to have a UV light with a red sensitivephotodiode nearby (or some other wavelength shifted band) to act as abinary test for healthy tissue, which would auto-fluoresce at a veryparticular wavelength.

Conductivity sensors can be used to determine the difference betweenliving and dead tissue or to show a change in impedance due to a woundbeing opened up in morbid tissue. Conductivity sensors can includeAg/AgCl electrodes and an impedance analyser. The conductivity sensorscan be used to measure the change of impedance of a region of woundgrowth by measuring the impedance of the surrounding tissue/area. Insome embodiments, the sensor array can utilize conductivity sensors tomeasure the change in conductivity on perimeter electrodes due to awound size or wound shape change. In some embodiments, the conductivitysensors can be used in the wound bed or on the perimeter of the wound.

In some embodiments, pH changing pads can be used as a pH sensor. Aspectrometer and a broadband white light source can be used to measurethe spectral response of the pH dye. The illumination and imaging can beprovided on the surface of the wound dressing that is in contact withthe wound and at the same side as the fluid application, the bottomsurface. Alternatively, in some embodiments, the illumination andimaging source can be provided on the surface of the wound dressingopposite the bottom surface and away from fluid application or the topsurface of the dressing.

In some embodiments, pulse oximetry SpO2 sensors can be used. To measurehow oxygenated the blood is and the pulsatile blood flow can beobserved. Pulse oximetry measurements work by taking a time resolvedmeasurement of light absorption/transmission in tissue at two differentoptical wavelengths. When hemoglobin becomes oxygenated, its absorptionspectrum changes with regards to non-oxygenated blood. By taking ameasurement at two different wavelengths, one gains a ratio metricmeasure of how oxygenated the blood is.

The components in the sensor array can be connected through multipleconnections. In some embodiments, the thermistors can be arranged ingroups of five. Each thermistor is nominally 10 kΩ, and each group offive has a common ground. There are five groups of thermistors, giving atotal of 30 connections. In some embodiments, there can be nineconductivity terminals. Each conductivity terminal requires oneconnection, giving a total of 9 connections. In some embodiments, therecan be five SpO2 sensors. Each SpO2 sensor requires three connections,plus power and ground (these are covered separately), giving a total of15 connections. In some embodiments, there can be 10 color sensors. Eachcolor sensor comprises an RGB LED and an RGB photodiode. Each colorsensor requires six connections, however five of these are common toevery sensor, giving a total of 15 connections. Power and ground areconsidered separately. In some embodiments, there can be 5 pH sensors.The pH sensors can be a color-change discs, and can be sensed using thecolor sensors described above. Therefore, the pH sensors require noadditional connections. There can be three power rails, and seven groundreturn signals, giving a total of 10 common connections. In someembodiments, the sensor array can include 25 thermistor (MurataNCP15WB473E03RC), 9 conductivity terminal, 5 SpO2 (ADPD144RI), 10 RGBLED (such as KPTF-1616RGBC-13), 10 RGB Color Sensor, 10 FET, a printedcircuit board (PCB), and an assembly.

A control module can be used to interface with the sensor array. In someembodiments, the control module can contain a power source, such asbatteries, and electronics to drive the sensors. The control module canalso log data at appropriate intervals and allow data transfer to anexternal computing device, such as a personal computer (PC). The controlmodule can be customized to have various features depending on thesensors used in the sensor array and the data collected by the sensors.In some embodiments, the control module can be comfortable enough andsmall enough to be worn continuously for several weeks. In someembodiments, the control module can be positioned near the wounddressing or on the wound dressing. In some embodiments, the controlmodule can be positioned in a remote location from the wound dressingand accompanying sensor array. The control module can communicate withthe sensor array and wound dressing through electrical wires or throughwireless communication whether positioned on the dressing, near thedressing, or remote from the wound dressing. In some embodiments, thecontrol module can be adapted to be utilized with different sensorarrays and can enable easy replacement of the sensor array.

In some embodiments, the control module can include various requirementsand combination of features including but not limited to the featureslisted in Table 1 below.

TABLE 1 OPTIONAL FEATURES FOR CONTROL MODULE 7 day operation from asingle set of batteries 28 day local, non-volatile, storage capacityEasy to charge, or to replace battery Wireless link to PC/tablet (suchas Bluetooth) Wired link to PC (optional, micro-USB) Drive electronicsfor thermistors Drive electronics for conductivity sensors Driveelectronics for optical sensors Drive electronics for SpO2 sensors Powermanagement Real Time Clock (RTC) to allow accurate data logging, andcorrelationwith other measurands Ability to change sample rates andintervals (useful for SpO2) for each sensor Indication of status viaLED, such as (Green: Awake; Flashing green: Charging; Blue: Wirelesslink established; Flashing blue: Wireless data transfer; Yellow: Wiredlink established; Flashing yellow: Wired data transfer; Red: Batterylow; Flashing red: Battery very low

FIG. 3E illustrates a block diagram 330 of a control module according tosome embodiments. The block diagram of the control module includes aconductivity driver box 391 displaying features of the conductivitydriver. Box 392 shows the features of the thermistor interface and box393 shows the features of the optical interface. The control module caninclude a controller or microprocessor with features similar to thoseshown in box 394. Real time clock (RTC), Status LEDs, USB connector,Serial Flash, and Debug Connector can be included as features of thecontrol module as shown in FIG. 3E.

In some embodiments, the microprocessor can have one or more of thefollowing features: 2.4 GHz or another suitable frequency radio (eitherintegrated, or external); Supplied Bluetooth software stack; SPIinterface; USB (or UART for external USB driver); I2C; 3 channel PWM; 32GPIO; or 6-channel ADC. In some embodiments, the device can require atleast 48 I/O pins or possibly more due to banking limitations. Bluetoothstack typically requires—20 kB on-board Flash, so a minimum of 32 kB canbe required. In some embodiment, 64 kB can be required if complex dataprocessing is considered. The processor core can be ARM Cortex M4 or asimilar processor core. In some embodiments, the parts can include ST'sSTM32L433LC or STM32F302R8, which would require an external radio, orNXP's Kinetis KW range including integrated radio.

In some embodiment, the control module can include a memory componentwhere the amount of local storage depends on the sample rate andresolution of the sensors. For example, an estimated data requirement of256 Mb (32 MB) can be met by using a serial Flash device from a numberof manufacturers (Micron, Spansion).

The control module can utilize one or more analogue switches. In someembodiments, analogue switches with good on resistance and reasonablebandwidth can be used. For example, Analog Devices' ADG72 or NXP'sNX3L4051 HR can be used. Based on the initial system architecture, 8 ofthese will be required.

The control module can incorporate a power source, such as a battery.For example, a 300 mWh/day battery can be used. For 7 days this is 2100mWh. This could be provided by: a 10 days, non-rechargeable, ER14250(14.5 mm diameter×25 mm) LiSOCl2 cell; or a 7 days, rechargeable, Li14500 (14.5 mm diameter×500 mm) Li-Ion.

The control module can incorporate a real time clock (RTC). The RTC canbe chosen from any RTC devices with crystal. The control module can alsoinclude miscellaneous resistors, capacitors, connectors, chargecontrollers, and other power supplies.

The PCB of the control module can be a 4-layer board, approximately 50mm×20 mm, or 25 mm×40 mm. The type of PCB used can be largely driven byconnection requirements to sensor array.

The enclosure of the control module can be a two-part moulding, withclip features to allow easy access for changing sensor arrays orbatteries.

The data collected through the sensor array can be passed through thecontrol module and processed by host software. The software may beexecuted on a processing device. The processing device can be a PC,tablet, smartphone, or other computer capable of running host software.The processing device executing the software can be in communicationwith the control module through electrical wires or through wirelesscommunication. In some embodiments, the software may be configured toprovide access to the data held on the control module, but not toperform big-data analysis. The host software can include an interface tothe control module via Bluetooth or USB. In some embodiments, the hostsoftware can read the status of control module, download logged datafrom control module, upload sample rate control to control module,convert data from control module into format suitable for processing bybig-data analysis engine, or upload data to cloud for processing byanalysis engine.

The software may be developed for PC (Windows/Linux), tablet orsmartphone (Android/iOS), or for multiple platforms.

In some embodiments, a source of negative pressure (such as a pump) andsome or all other components of the topical negative pressure system,such as power source(s), sensor(s), connector(s), user interfacecomponent(s) (such as button(s), switch(es), speaker(s), screen(s),etc.) and the like, can be integral with the wound dressing. In someembodiments, the components can be integrated below, within, on top of,or adjacent to the backing layer. In some embodiments, the wounddressing can include a second cover layer or a second filter layer forpositioning over the layers of the wound dressing and any of theintegrated components. The second cover layer can be the upper mostlayer of the dressing or can be a separate envelope that enclosed theintegrated components of the topical negative pressure system.

As used herein the upper layer, top layer, or layer above refers to alayer furthest from the surface of the skin or wound while the dressingis in use and positioned over the wound. Accordingly, the lower surface,lower layer, bottom layer, or layer below refers to the layer that isclosest to the surface of the skin or wound while the dressing is in useand positioned over the wound.

Component Positioning

In some embodiments, electrical or electronic components, such assensors, connections, or the like, can be placed or positioned on orembedded in one or more wound dressing components, which can be placedin or on the wound, skin, or both the wound and the skin. For example,one or more electronic components can be positioned on a wound contactlayer side that faces the wound, such as the lower surface 224 of thewound contact layer 222 in FIG. 1B. The wound contact layer can beflexible, elastic, or stretchable or substantially flexible, elastic, orstretchable in order to conform to or cover the wound. For example, thewound contact layer can be made from a stretchable or substantiallystretchable material, such as one or more of polyurethane, thermoplasticpolyurethane (TPU), silicone, polycarbonate, polyethylene, polyimide,polyamide, polyester, polyethelene tetraphthalate (PET), polybutalenetetreaphthalate (PBT), polyethylene naphthalate (PEN), polyetherimide(PEI), along with various fluropolymers (FEP) and copolymers, or anothersuitable material. In some instances, one or more electronic componentscan be alternatively or additionally placed or positioned on or embeddedin any one or more of a transmission layer, absorbent layer, backinglayer, or any other suitable layer of the wound dressing.

In some implementations, while it may be desirable for the wound contactlayer to be stretchable to better conform to or cover the wound, atleast some of the electronic components may not be stretchable orflexible. In such instances, undesirable or excessive localized strainor stress may be exerted on the one or more electronic components, suchas on the supporting area or mountings of an electronic component, whenthe wound is dressed with the wound dressing and the wound contact layeris positioned in or over the wound. For example, such stress can be dueto patient movement, changes in the shape or size of the wound (such as,due to its healing), or the like. Such stress may cause movement,dislodgment, or malfunction of the one or more electronic components(for example, creation of an open circuit from a pin or anotherconnector becoming disconnected). Alternatively or additionally, it maybe desirable to maintain the position of one or more electroniccomponents, such as one or more sensors, in the same or substantiallysame location or region on the wound contact layer with respect to thewound (such as, in contact with the wound) so that measurementscollected by the one or more electronic components accurately capturechanges over time in the same or substantially same location or regionof the wound. While the surface of the stretchable wound contact layermay move when, for example, the patient moves, it may be desirable tohave the one or more electronic components be located in the samelocation or region with respect to the wound.

As described herein, in some embodiments, one or more stiff, rigid, ornon-stretchable or substantially stiff, rigid, or non-stretchableregions, such as one or more regions of non-stretchable or substantiallynon-stretchable material, can be mounted, positioned, or placed on thewound contact layer (or another suitable wound dressing component) forsupporting one or more electronic components. Mounting, positioning, orplacing one or more electronic components in the one or morenon-stretchable or substantially non-stretchable regions can preventformation of localized stress or assist with maintenance of the positionof the one or more electronic components with respect to the wound. Insome instances, one or more electronic components can be alternativelyor additionally flexible, such as mounted or printed on or supported byone or more flexible materials. For example, flexible plastic sheets orsubstrates, such as polyimide, polyether ether ketone (PEEK), polyester,silicone, or the like, can be used.

FIGS. 4A-4C illustrate a wound dressing 400 with a plurality ofelectronic components according to some embodiments. As is shown, asheet or substrate 430 is configured to support one or more electroniccomponents, including an electronic component or module 402 with aplurality of connectors 404 and a plurality of electronic connections410, and non-stretchable or substantially non-stretchable regions 422and 424. The substrate 430 can be a stretchable or substantiallystretchable wound contact layer as described herein. The electronicmodule 402 can be any electronic component described herein, such as asensor, light source (such as an LED, temperature sensor, opticalsensor, etc.), controller or processor (such as a communicationprocessor), or the like. Electronic connections 410 can be tracksprinted on the substrate 430, such as using conductive copper,conductive ink (such as silver ink, graphite ink, etc.), or the like. Atleast some of the electronic connections 410 can be flexible orstretchable or substantially flexible or stretchable. Connectors 404 canbe configured to electronically connect the electronic module 402 to theelectronic connection 410 (as illustrated in FIG. 4B), which in turn canbe connected to other electronic modules (not shown) positioned on thesubstrate 430, on or in other components of the wound dressing, orexternal to the wound dressing. Connectors 404 can be pins, leads,bumps, or the like. Additionally or alternatively a socket can be usedto support and electronically connect the electronic module 402. Regions422 and 424 can include non-stretchable or substantially non-stretchablematerial, such as one or more of suitable adhesive, epoxy, polyester,polyimide, polyamide, PET, PBT, or another type of material with a highYoung's modulus. One or more of the regions 422 and 424 can be printedon the substrate 430. As is used herein, printing material on asubstrate can include one or more of laminating, adhering, or any othersuitable technique.

FIG. 4B illustrates components positioned on the substrate 430. Asshown, the electronic module 402 is mounted to or supported by theregion 422. A portion or part of the electronic connections 410 ismounted to or supported by the region 424. Also illustrated are slits,holes, or perforations formed in the substrate 430 according to someembodiments. As described herein, the substrate 430 can be perforatedusing one or more of a cold pin perforation, hot pin perforation, laserablation perforation, ultrasonic or ultrasound perforation, or the liketo make the wound contact layer permeable to liquid and gas. In someimplementations, one or more utilized perforation processes can generatea flat or substantially substrate around the hole rather than an unevensurface (such as donut-shaped surface). Having a flat or substantiallyflat substrate can assist in generating a homogenous layer whenconformal coating is applied (such as, via spray, brush, or the like asdescribed herein). Further, using a perforation process that leaves thesurface of the substrate uneven or substantially uneven can introduce agreater risk of dislodging one or more components, such as theelectronic connections 410 or the electronic module 402 whenperforations are made around the components.

In certain implementations, perforations are made or patterned aroundone or more components placed on the substrate 430, such as theelectronic connections 410, the electronic module 402, or the regions422 or 424. As explained herein, component indexing can be used toautomatically locate position of the one or more components on thesubstrate 430 so that the one or more components are not damaged byperforations. In some embodiments, the substrate can be perforatedbefore one or more components illustrated in FIG. 4A as placed on thesubstrate.

FIG. 4C illustrates optional application of one or more of coating 440or one or more adhesive regions 452, 454, 456 according to someembodiments. Coating 440 can be conformal coating configured toencapsulate or coat one or more of the substrate 430 or componentssupported by the substrate, such as the electronic connections 410 orthe electronic module 402. Coating 440 can provide biocompatibility,shield or protect the electronics from coming into contact with fluids,or the like. Coating 440 can be one or more of a suitable polymer,adhesive, such as 1072-M UV, light, or thermal curable or curedadhesive, Optimax adhesive, parylene (such as, Parylene C), silicon,epoxy, urethane, acrylated urethane, or another suitable biocompatibleand stretchable material. Coating 440 can be thin, such as about 100microns thick, less than about 100 microns thick, or more than about 100microns thick. Coating 440 can be applied and cured using one or more ofUV, light, or thermal curing. In some implementations, coating 440 canbe applied on the other side of the substrate 430 (or side facing awayfrom the wound) particularly if the substrate is not impermeable tofluid. In some embodiments, coating is optional.

One or more adhesive pads, tracks, or regions 452, 454, 456 can beapplied to the wound facing side of the substrate 430 as illustrated. Insome embodiments, first adhesive region 452 can be shaped, sized, orpositioned to affix the electronic module 402 in contact with orrelative to a first specific or particular part of the wound, such as afirst specific or particular area, region, or location in contact withor relative to the wound. Adhesive region 452 can be shaped and sizedsimilarly to the region 422 or the electronic module 402 to affix themodule to a particular location in the wound. Similarly, second adhesiveregion 454 can be shaped, sized, or positioned to affix the portion orpart of the electronic connections 410 supported by the region 424relative to a second specific or particular part of the wound, such as asecond specific or particular area, region, or location in contact withor relative to the wound. Another (third) region of adhesive 456 isillustrated which can affix another part of the wound contact layer toanother (third) specific or particular part of the wound, such asanother (third) specific or particular area, region, or location incontact with or relative to the wound. Adhesive material can be one ormore of silicone, such as two-part silicone, one-part silicone, gel,epoxy, acrylic-based material, or another suitable material. Adhesivecan be applied and cured using one or more of UV, light, or thermalcuring. For example, adhesive can be printed, sprayed, coated, or thelike and then cured by UV, light, thermal curing, catalytic, watervapor, or the like. In some embodiments, adhesive is optional.

In some embodiments, one or more adhesive regions can be patterned toposition or affix specific components in particular areas, regions, orlocations in contact with or relative to the wound even while thesubstrate 430 is under stress or strain. While the substrate may strainbetween the adhesive regions, the electronic module 402, such as asensor, will remain in the same location in contact with or relative tothe wound (due to the adhesive region 452), thus maintaining the mostrepeatable signal, and the portion or the part of the electronicconnections 410 will remain in the same location in contact with orrelative to the wound such that it will not be dragged across the wound(due to the adhesive region 454) when the substrate 430 undergoesstrain. Additionally, the supporting area or mountings of the electronicmodule 402 will not be put under as much stress because the body (forinstance, the skin, which may strain about 20%) will relieve some of thestress (for example, due to the attachment of the wound contact layer tothe wound by the one or more adhesive regions) and the substrate willyield around the electronic module. Similar stress relief can beprovided to the portion of the electronic connection 410 which isoverlaid by the adhesive region 454. This can prevent malfunction of theone or more electronic components.

In certain embodiments, pattern of the adhesive regions can be based onthe positioning of the one or more electronic components, which can bedetermined using indexing as described herein. As explained herein, itmay be desirable to pattern the adhesive to equalize the stress orstrain on the wound contact layer. Adhesive can be patterned tostrengthen or support certain areas or regions, such as regions whereone or more electronic components are placed, while weakening (or makingless rigid) other regions to distribute the stress or to avoid strainingthe one or more electrical components. For example, it may be desirableto cover at least 50% or more of the wound facing surface of the woundcontact layer with the adhesive. In certain implementations, adhesivecan be applied to cover or substantially cover the entire wound facingside of the wound contact layer.

In some embodiments, adhesive material used to form the one or moreadhesive regions can be non-stretchable or substantiallynon-stretchable. One or more regions of the non-stretchable orsubstantially non-stretchable material, such as regions 422 and 424, maynot be used or may be sized or shaped differently from one or moreadhesive regions.

Although a single electronic module 402 is illustrated in FIGS. 4A-4C,in certain implementations, a plurality of electronic modules can beused. One or more of the additional electronic modules or one or moreelectronic connections 410 interconnecting the electronic module 402 andthe additional electronic modules can be placed on one or moreadditional non-stretchable or substantially non-stretchable regions.Additionally or alternatively, adhesive regions can be placed to furtheraffix the one or more electronic modules or electronic connections incontact with or relative to the wound as described herein.

Component Encapsulation and Stress Relief

As described herein, biocompatible coating can be applied to the woundcontact layer or electronic components positioned on the wound contactlayer. In some embodiments, the wound contact layer includes a thin,flexible substrate that conforms to the wound. For example, thesubstrate can be made from stretchable or substantially stretchablematerial or film, such as polyurethane, TPU, silicone, polycarbonate,polyethylene, polyimide, polyamide, polyester, PET, PBT, PEN, PEI, alongwith various FEP and copolymers, or another suitable material. Thesubstrate may not be biocompatible. Coating can be flexible. Coating caninclude one or more suitable polymers, adhesives, such as 1072-Madhesive (for example Dymax 1072-M), 1165-M adhesive (such as, Dymax1165-M), parylene (such as, Parylene C), silicones, epoxies, urethanes,acrylated urethanes, acrylated urethane alternatives (such as, HenkelLoctite 3381), or other suitable biocompatible and substantiallystretchable materials. Coating can be thin coating, for example, fromabout 80 microns or less up to several millimeters or more. As describedherein, coating can be applied by laminating, adhering, welding (forinstance, ultrasonic welding), curing by one or more of light, UV, heat,or the like. Coating can be transparent or substantially transparent topermit optical detection. Coating can retain bond strength whensubjected to sterilization, such as EtO sterilization. Coating can havehardness lower than about A100, A80, A50 or lower. Coating can haveelongation at break higher than about 100%, 200%, 300% or more. Coatingcan have viscosity of about 8,000-14,500 centipoise (cP). In some cases,coating can have viscosity no less than about 3,000 cP. In some cases,coating can have viscosity less than about 3,000 cP. Coating can befluorescent.

It may be desirable for a substrate and electronic components supportedby the substrate to be conformable as the substrate and the electroniccomponents are intended to be positioned on or in the body. One propertyof conformability is the extensibility of the coating material as theelectronic components may need to be isolated from the wound. Coatingapplied to the substrate may need to have the ability to stretch withthe substrate (in case the substrate is stretchable or substantiallystretchable). Pairing the elongation characteristics of both thesubstrate and coating can maximize the desired properties of the device.In some examples, the substrate can be formed from TPU film. Coating canbe formed from acrylated urethane, such as 1165-M Dymax, 1072-M Dymax,or another suitable material as described herein.

The substrate may need to be coated evenly and comprehensively (forexample, the substrate may be encapsulated by the biocompatiblecoating). The substrate (for example, TPU) may by hydrophilic and,accordingly, may need to be encapsulated in hydrophobic coating tocreate a hydrophobic dressing to be placed on or in the wound.

FIGS. 5A-5B illustrate coating(s) of a wound dressing according to someembodiments. As described herein, one of the sides of a substrate 530 ofthe wound dressing can include a plurality of electronic components 402protruding from the surface. This is illustrated, for example, in FIGS.4A-4C where the electronic module 402 protrudes from the wound facingsurface of the substrate 430. As is shown in FIG. 5A, coating 440A canbe applied to the side of the substrate supporting electroniccomponents. As described herein, coating 440A can be biocompatible.Coating 440A can be hydrophobic. Coating 440A can be substantiallystretchable or extensible.

As shown in FIG. 5B, coating 440B can be applied to the opposite side ofthe substrate. This can be advantageous when a substrate is notbiocompatible or hydrophobic. Coating 440B can be biocompatible. Coating440B can be hydrophobic. Coating 440B can be substantially stretchableor extensible. Coatings 440A and 440B can be the same or different. Thesubstrate 530 can be encapsulated in the coating as shown in FIG. 5B.Although not illustrated, the left and right sides of the substrate 530are also encapsulated in the coating.

FIG. 6 illustrates coating a wound dressing with two biocompatiblecoatings according to some embodiments. Electronic components 402supported by the substrate 530 can be coated with coating 640A,particularly if the substrate 530 is stretchable or substantiallystretchable. As described herein, coating 640A can be non-stretchable orsubstantially non-stretchable to provide stress relief for theelectronic components (which may include electronic modules orelectronic connections). Coating 640A can be applied on and around theelectronic components. Coating 640A can be biocompatible. Coating 640Acan be hydrophobic.

Non-stretchable or substantially non-stretchable coating describedherein, such as the coating 640A, can be formed from acrylated ormodified urethane material (such as, Henkel Loctite 3211). For example,coating can be one or more of Dymax 1901-M, Dymax 9001-E, Dymax 20351,Dymax 20558, Henkel Loctite 3211, or another suitable material. Coatingcan have viscosity from about 13,500 cP to 50,000 cP before being curedor from about 3,600 cP to about 6,600 cP before being cured. In somecases, coating can have viscosity of no more than about 50,000 cP.Coating can have hardness from about D40 to about D65 and/or linearshrinkage of about 1.5-2.5%. Coating can be transparent or substantiallytransparent to permit optical detection. Coating may be colorless orsubstantially colorless. Coating 640A can be fluorescent. Coating canretain bond strength when subjected to sterilization, such as EtOsterilization.

As illustrated, coating 640B can be applied to the remaining surface ofthe side of the substrate supporting the electronic components. Coating640B can also be applied to the opposite side of the substrate. Althoughnot illustrated, the left and right sides of the substrate 530 are alsoencapsulated in the coating. Coating 640B can be biocompatible. Coating640B can be hydrophobic. Coating 640B can be substantially stretchableor extensible. Coating 640B may be similar to any of the one or moreflexible or substantially flexible coatings described herein. Forexample, coating 640B may be formed from acrylated urethane or itsalternative, such as 1165-M Dymax, 1072-M Dymax, Henkel Loctite 3381 oranother suitable material.

In some embodiments, non-stretchable or substantially non-stretchablecoating may not be biocompatible. As illustrated in FIG. 7, theelectronic components 402 supported by the substrate 530 are coated withnon-stretchable or substantially non-stretchable coating 740A, which isnot biocompatible. A second coating 740B can be applied to the side ofthe substrate 530 supporting the electronic components. Coating 740B canbe applied over coating 740A. Coating 740B can also be applied to theopposite side of the substrate. Although not illustrated, the left andright sides of the substrate 530 are also encapsulated in coating 740B.Coating 740B can be biocompatible. Coating 740B can be hydrophobic.Coating 740B can be substantially stretchable or extensible.

Coating a thin, flexible substrate with biocompatible material is nottrivial because the substrate may need to be coated on the side whereelectronic components are positioned and on the opposite side. Inaddition, the substrate may need to be coated evenly and comprehensively(for example, the substrate may be encapsulated by the biocompatiblecoating).

In some embodiments, a device 500 for coating a wound contact layer asshown in FIG. 8 can be used. The device 500 includes a bottom frame 514and a top frame 512 attached to the frame 514. Substrate 530 is held intension or substantially in tension between the frames 514 and 512. Insome implementations, the substrate 530 can be mounted on a backing,such as a substantially rigid backing made of material with high aYoung's modulus (for instance, PET, PBT, or another suitable material).The backing can be shaped as a frame and can be attached to theperiphery of the substrate 530. The substrate 530 is clamped or held inthe device 500 so that the substrate does not sag. In someimplementations, the frame 514 can be mounted on a base as describedherein.

In some embodiments, coating can be applied thinly and evenly. Forexample, coating can be sprayed. In some embodiments, biocompatiblecoating can be applied to the wound contact layer by a device 600 ofFIG. 9. As is illustrated, the substrate 530 is held by the device 500.Coating is applied by the device 610, which can spray the coatingmaterial on both sides of the substrate 530. For example, after a firstside of the substrate 530 has been coated, the device 500 can be flippedto coat the opposite side of the substrate 530. The frames 514 and 512can be made from material to which coating does not stick. Such materialcan include one or more of PTFE, nylon, or another suitable material.For example, PTFE frames are illustrated in the figures.

As described herein, one of the sides of the wound contact layer caninclude a plurality of electronic components protruding from thesurface. This is illustrated, for example, in FIGS. 4A-4C where theelectronic module 402 protrudes from the wound facing surface of thesubstrate 430. To efficiently and accurately coat the opposite side ofsuch substrate, a plate or mold 700 of FIG. 10 can be used in someembodiments. As is illustrated, the mold 700 has recesses 710 into whichone or more electronic components can be positioned. Such recesses canalso be referred to as indentations, notches, engravings, wells, orcontours. In some embodiments, the recesses 710 are shaped to allow theelectronic components to be comfortably positioned. The opening area ordepth of the recesses 710 can be larger than the combined area or depthof the electronic components and the coating to provide comfortablesupport. Positioning the one or more electronic components into one ormore recesses permits the opposite side of the substrate to be held flator substantially flat or smooth so that coating can be evenly applied tothat side. In addition, the mold 700 can prevent the substrate fromsagging.

In certain implementations, the mold 700 can be made from material towhich coating does not stick. Such material can include one or more ofPTFE, nylon, or another suitable material. For example, a PTFE mold isillustrated in the figures.

In some embodiments, a mold can include recesses 710 shaped or arrangedto permit coating of various substrates that may have differentarrangements of electronic components. The mold 700 can includeredundant or additional recesses 710 that are not in use when, forexample, a first substrate is being coated. At least some of suchadditional recesses 710 can be used when a second substrate is beingcoated because they are arranged or shaped to permit positioning of theelectronic components of the second substrate.

FIGS. 11 and 12A-12B illustrate a device 800 for coating a wounddressing according to some embodiments. In the device 800, the mold 700is positioned on a base 518, which provides support. The base 518 can bemade from material to which coating does not stick. Such material caninclude one or more of nylon, PTFE, or another suitable material. Forexample, a nylon base is illustrated in the figures.

The frame 514 is also positioned on the base as illustrated. In someembodiments, the frame 514 includes one or more pins that are configuredto attach to one or more holes on the base. The pins can be dowel pins.

The frame 512 can also be attached to the frame 514 as illustrated. Incertain implementations, the attachment is performed using one or morepins positioned on one of the frames and matching holes positioned onthe other frame. The pins can be dowel pins.

In the illustrated arrangement, a substrate (not shown) can bepositioned with the side supporting the electronic components placed onthe mold 700 and be held in tension between the frames 514 and 512. Thiscan permit applying the coating to the side opposite that which supportsthe electronic components. Subsequently, the mold 700 can be removed,the substrate can be flipped and positioned between the frames 514 and512 as described herein so that the side supporting the electroniccomponents can be coated.

In some embodiments, a side of the substrate supporting the electroniccomponents is coated first. The device 500 (without the mold) or 800(with the mold) can be used hold the substrate between the frames 514and 512. The mold 700 can have thickness that takes into accountthickness of the coating. The mold 700 can have thickness of the frame514 minus the thickness of the coating. For example, the frame 514 canbe 10 mm thick and the mold 700 can be 9.85 mm think when 150 micron(0.15 mm) coating is applied to a side of the substrate supporting theelectronic components. When the substrate is flipped and the coated sidesupporting the electronic components is positioned on the mold 700, thesubstrate is precisely leveled on the mold 700 to be held in tensionbetween the frames 514 and 512 to allow coating of the opposite(non-component) side of the substrate.

In some implementations, rigid or substantially rigid release layer orliner 1010 as illustrated in FIG. 13 can be additionally oralternatively used. Release liner 1010 can be applied to the substrate530 to keep the substrate in tension or substantially in tension so thatthe substrate can be coated. Release liner 1010 can be applied to afirst side of the substrate 530 (for example, the side not supportingthe electronic components), permitting the opposite side to be coated.Afterwards, release liner 1010 can be removed and the other side (forexample, the side supporting the electronics) can be coated. Releaseliner 1010 may be applied to the coated side to permit coating of theother side. Release liner can be shaped as a window frame as illustratedin FIG. 13. Release liner can be adhered to the substrate or attached byany other suitable method.

In certain implementations, release liner 1010 can serve as the backingdescribed herein.

In some embodiments, as illustrated in FIGS. 14A-14B, a mold of thewound contact layer can be cast to enable the wound contact layer to beheld flat or substantially flat during coating. As shown in FIG. 14A,casting material 1110 can be poured to cast a form or mold 1120. Themold includes recesses 1122 sized, shaped, and arranged to match theplurality of electronic components supported by a wound contact layer.Such recesses can also be referred to as indentations, notches,engravings, wells, or contours.

FIG. 14B illustrates coating the substrate 530 using the mold 1120. Thesubstrate 530 includes a plurality of electronic components 1102protruding from the surface of the substrate. The electronic components1102 are positioned in the recesses 1122 of the mold 1120 so that theopposite side of the substrate is substantially flat. Coating 1140 isevenly applied to encapsulate the opposite side of the substrate and itssides.

The side of the substrate 530 supporting the components can be coatedbefore or after coating of the opposite side. For example, a releaseliner, such as the liner 1010, or another backing can be applied to theopposite, uncoated side to coat the side of the substrate 530 supportingthe electronic components. Afterwards, the substrate 530 can be flippedand placed in the mold 1120 to coat the opposite side as illustrated inFIG. 14B. As described herein, the recesses 1122 of the mold 1120 can beshaped and sized to account for the coating on the electroniccomponents.

As described herein, in some embodiments, acrylated urethanes can beused as coating material as these polymers have suitable adhesiveproperties and extensibility. Spray coating acrylated urethanes usingthe compressed air or inert gas can lead to oxygen inhibition of thepolymerization reaction to cure the acrylated urethanes. Removal ofoxygen from the system leads to removal of its negative effect on thepolymerization reaction to cure the acrylated urethanes.

FIG. 15 illustrates spray coating a wound dressing according to someembodiments. The spray device 1200 includes a dispenser 1230 connectedto a pressurized cylinder 1220 storing air or inert gas. Force ofcompressed air or gas causes coating 1240 to be sprayed from thedispenser 1230 onto the substrate 530. The substrate can be held intension or substantially in tension by device 1210, which can include atleast one of a plurality of frames or a mold as described herein.Coating 1240 can be biocompatible. Coating 1240 can be hydrophobic.Coating 1240 can be substantially stretchable or extensible.

In some embodiments, non-stretchable or substantially non-stretchablecoating can be applied to at least some of the plurality of electroniccomponents. FIG. 16 illustrates applying non-stretchable material to awound dressing according to some embodiments. The spray device 1000includes a dispenser 1030 connected to a pressurized cylinder 1020storing air or inert gas. Force of compressed air or gas causes coating1110 to be sprayed from the dispenser 1030 onto a connecting track 410.Coating 1110 can be stretchable or substantially non-stretchable.Alternatively or additionally to coating the track 410, an electronicmodule can also be coated.

In some embodiments, a single layer of stretchable or non-stretchablecoating can be applied. In some embodiments, multiple layers ofstretchable or non-stretchable coating can be applied. For example,multiple layers of non-stretchable coating can be applied to achievedesired stiffness or rigidity.

FIGS. 17A-17B illustrate comparisons of performance without and withnon-stretchable material according to some embodiments. FIG. 17Aillustrates how much an electrical connection that has not been coatedwith non-stretchable or substantially non-stretchable coating stretches.Stretching may be caused, for example, by movement of the patient.

FIG. 17B illustrates how much an electronic connection that has beencoated with non-stretchable or substantially non-stretchable coatingstretches. As is illustrated, both uncoated and coated electronicconnections 410A and 410C are about the same length when not stretched.However, uncoated electronic connection 410B stretches to a much greaterlength than the coated electronic connection 410D.

In some embodiments, wound dressings described herein may need to complywith one or more safety standards, such as IEC 60601 standard for thesafety and effectiveness of medical electrical equipment. Such one ormore standards can require highly rigorous test method(s) to ensure theelectrical safety of the wound dressing. Coatings described herein, suchas coatings 440, 440A, 440B, 640A, 640B, 740A, 740B, 1240 can be appliedto the substrate to ensure compliance with the applicable safetystandard(s). For example, coatings can protect the electrical componentsof the wound dressing against liquid ingress, ensure electrical safety,or the like. Coatings described herein can be formed from material(s)that comply with the one or more applicable safety standards.

In some embodiments, coating can include one or more pre-existingmaterials, such as film. Such pre-existing materials can be manufacturedor tested to comply with the one or more applicable safety standards,such as IEC 60601 standard, before applying the one or more materials tothe substrate as described herein. In certain implementations,pre-existing material can be TPU, acrylated urethane, or anothermaterial.

In some implementations, coating can be applied over the electroniccomponents, which may cause the coating layer to experience localizedthinning or stretching. This may be due to uneven surface of thesubstrate as a result of placement of the electronic components. In somecases, localized thinning or stretching may be present or be detectablewhen the coating is not sprayed.

In certain embodiments, electromagnetic/radiofrequency shielding can beapplied to the coated surface to protect the electronic components fromelectromagnetic interference. For example, conductive ink can be used.The ink can be silicone, silver, or the like.

Component Encapsulation and Stress Relief with a Perforated Substrate

In some embodiments, the substrate 430 can include one or moreperforations. Such one or more perforations can improve one or more ofthe accuracy, efficiency, or speed of the coating process as describedbelow. The one or more perforations can be made in the substrate 430 toimprove the coating process.

FIG. 18 illustrates a wound dressing 1800 with one or more perforationsaccording to some embodiments. The illustrated dressing 1800 includes asubstrate 430 supporting one or more electronic modules 402 electricallyconnected by one or more connectors 404 to one or more electronicconnections 410. The electric connection(s) between a module 402 and oneor more electronic connections 410 can be made by soldering 412 the oneor more connectors 404 of the module 402 to the one or more electronicconnections 410 or by other suitable means, such as using a socket,surface mounting, or the like. The substrate 430 includes one or moreperforations 470. As illustrated, a perforation 470 can be positionedunder the module 402. In some implementations, additional perforationscan be made under the module 402. In some cases, one or moreperforations can be made not under or away from the module 402.

Any of the one or more perforations 470 can provide escape for gas orair bubbles that may form when coating the substrate 430 and one or morecomponents supported by the substrate. As described herein, removal ofoxygen or air can lead to removal of its negative effect on thepolymerization reaction to cure acrylated urethanes. FIG. 19Aillustrates coating 1300A of the wound dressing 1800 according to one ormore embodiments. As described herein (for example, with reference toFIGS. 6-7), the one or more modules 402 (and one or more electronicconnections 410) can be coated with non-stretchable or substantiallynon-stretchable coating to provide stress relief. FIG. 19A illustratessuch coating 480 being applied. The coating 480 can flow under themodule 402 as illustrated. This can result in any gas or air escapingthrough any of the one or more perforations 470 instead of the gas orair being trapped within the coating or under the module 402. In somecases, coating 480 has sufficient viscosity to facilitate efficientflow, while not being too viscous to not provide the necessary stressrelief for the module 402 as material with higher viscosity may notfully conform around the module 402. As described herein, coating 480can have viscosity of about 13,500-50,000 cP or about 3,600-6,600 cP(for example, about 17,000 cP). In some cases, coating can haveviscosity of no more than about 50,000 cP. As illustrated, any of theone or more perforations 470 can be completely or partially filled withthe coating 480. In some implementations, the coating process can besped up by the generation of a pressure difference across the substrate430. For example, applying higher pressure on the top side of thesubstrate 430 (component side as shown) than on the bottom, oppositeside of the substrate 430 can force the coating 480 to flow through theperforation 470. In some implementations, higher pressure can be appliedby spray coating the top side of the substrate 430, such as spraycoating with compressed air or inert gas.

FIG. 19B illustrates coating 1300 b of a wound dressing 1800 accordingto some embodiments. The wound dressing 1200 can already by coated withcoating 480 as described in connection with FIG. 19A. As describedherein, additional coating(s) can be applied to the wound dressing 1200.For example, as described with reference to FIGS. 5A-5B, such additionalcoating(s) can be one or more of biocompatible, hydrophobic, orsubstantially stretchable or extensible. The additional coating(s) canbe used to encapsulate or substantially encapsulate the substrate 430.

As illustrated in FIG. 19B, one or more of additional coatings 492 and494 can be applied to the wound dressing 1200. Coating 492 can beapplied to the top side (or component side) of the substrate 430.Coating 494 can be applied to the opposite, bottom side of the substrate430.

In some embodiments, one or more release liners may be used during theprocess of making or coating the wound dressing 1200. For example, therecan be a release liner (not shown) on the bottom side of the substrate430, which can be peeled off following the successful application ofcoating 492 and before coating 494 is applied. There can be anadditional liner applied to the top side of the substrate 430 prior tosoft coat 494 being applied, which may be removed thereafter. Using oneor more of such release liners can ensure that coating 492 is notapplied to the areas where coating 494 should be applied and vice versa.

Any one or more of the coatings 480, 492, or 494 can be applied usingany one or more of the approaches described herein. In some cases, anyof the one or more perforations 470 can be completely or partiallyfilled with one or more coatings described herein, such as one or morecoatings 480 or 494. In some implementations, any of the one or moreperforations can be partially filled with one or more coatings and canallow fluid, such as wound exudate, to pass through the wound dressing.

Additional examples of substrate embodiments and coating embodiments canbe found in International Application No. PCT/EP2018/059333 filed onApr. 11, 2018, entitled COMPONENT STRESS RELIEF FOR SENSOR ENABLEDNEGATIVE PRESSURE WOUND THERAPY DRESSINGS, and International ApplicationNo. PCT/EP2018/069883 filed on Jul. 23, 2018, entitled BIOCOMPATIBLEENCAPSULATION AND COMPONENT STRESS RELIEF FOR SENSOR ENABLED NEGATIVEPRESSURE WOUND THERAPY DRESSINGS, the disclosures of which are herebyincorporated by reference in their entireties.

Protection of Components with Coatings

FIGS. 20A-20B illustrates a wound dressing similar to the wound dressingdescribed with reference to FIGS. 4A-4C with a plurality of electroniccomponents according to some embodiments. As is shown, a sheet orsubstrate 2030 is configured to support one or more electroniccomponents, including an electronic component or module 2002 with aplurality of connectors 2004 and a plurality of electronic connections2010. The substrate 2030 can be a stretchable or substantiallystretchable wound contact layer as described herein. The electronicmodule 2002 can be any electronic component described herein, such as asensor, light source (such as an LED, temperature sensor, opticalsensor, etc.), controller or processor (such as a communicationprocessor), or the like. Electronic connections 2010 can be tracksprinted on the substrate 2030, such as using conductive copper,conductive ink (such as silver ink, graphite ink, etc.), or the like. Atleast some of the electronic connections 2010 can be flexible orstretchable or substantially flexible or stretchable. Connectors 2004can be configured to electrically connect the electronic module 2002 tothe electronic connection 2010 which in turn can be connected to otherelectronic modules (not shown) positioned on the substrate 2030 or toother components of the wound dressing or external to the wounddressing. Connectors 2004 can be pins, leads, bumps, or the like.Additionally or alternatively a socket can be used to support andelectronically connect the electronic module 2002. The substrate andconnectors can be coated with non-stretchable or substantiallynon-stretchable material, as described with reference to FIGS. 4A-4Cpreviously, to reinforce or strengthen the electrical connection formedby a connector 2004. Coating can be applied at least to the substrate(such as, under a connector 2004) or a connector 2004.

Coating can be applied to the substrate 2030 to protect the connectionregion 2012. The connection region 2012 can include an electronicconnector 2004 at the point between the electronic module 2002 and theelectrical connections 2010. Alternatively or additionally, theconnection region 2012 can include at least a part of an electronicmodule 2002 and an electrical connection 2010. For example, theconnection region 2012 can include the connector 2004 and the area ofthe wound contact layer or substrate (including one or more electroniccomponents or electronic tracks) supporting or adjacent to theconnector. In some embodiments, a hard or non-stretchable orsubstantially non-stretchable adhesive material can be applied to theconnection region 2012 to bolster or strengthen the connection region2012.

In some embodiments, the coating can cure as a solid material using anyof the curing techniques described herein. This can cause the areaswhich already protrude from the substrate (such as one or moreelectronic modules) to become more exaggerated, which may have thepropensity to cause discomfort or damage to the tissue when in use dueto pressure. Therefore, it can be advantageous to balance the need toprotect the weak connection regions of the component and minimize therisk of pressure related tissue damage to the patient when the substrateis in use.

Different application patterns can be used to apply the strengtheningadhesive coating to the connection region 2012. FIGS. 21A-21D illustratedifferent application patterns of the non-stretchable or substantiallynon-stretchable adhesive coating material 2013 that can be used to coatthe connection region 2012.

As illustrated in FIG. 21A a layer of coating material 2013 can beapplied as a ball or large dot of material over the entire electronicmodule 2002 and connection region 2012. This application can provide alarge area of protection and strengthen the entire electronic module.

In some embodiments, a large mass of adhesive over an already protrudingarea can cause more patient discomfort and may allow an air pocket tobecome trapped under the electronic module (as described herein), whichcould expand when cured (such as, temperature cured in an oven).Therefore, it could be advantageous to apply the non-stretchable orsubstantially non-stretchable adhesive coating material in distinctpatterns around the electronic module.

FIG. 21B illustrates a layer of coating material 2013 applied around theperimeter of the electronic module 2002. The application of the coatingmaterial 2013 around the perimeter of the electronic module 2002 canensure the full perimeter is protected and strengthened, while notincreasing the height profile (or bulge) of the electronic module 2002.

In some cases, the coating material 2013 can be applied to an areaaround a perimeter of an electronic component at areas associated withthe at least one connector. In some cases, the coating material 2013 canbe applied to an area around a perimeter of an electronic component atareas not associated with the at least one connector.

In some embodiments the coating material 2013 can coat the connectors2004 in the connection regions 2012. FIG. 21C illustrates a line orstrip of coating material 2013 over the connectors 2004 in theconnection region 2012. FIG. 21D illustrates the application of ball ordot pattern (or any other suitably shaped pattern) of coating material2013 over the connectors 2004 in the connection region 2012. Theillustrations in FIGS. 21C-21D include a minimal amount of adhesiveapplied only to weak areas on the substrate that could benefit frombeing reinforced. This application can minimize the bulge and thusminimize patient discomfort. This application pattern also allows air toescape from under the electronic component if it expands during curingas the illustrated pattern does not seal the perimeter of the electronicmodule 2002. Any pattern can be utilized to coat the connectors in theconnection region. In some cases, for example, the pattern can be set tocontour the external edge of the component.

In some cases, the coating material 2013 can be applied over an edge ofthe electronic component or electronic module 2002. The coating material2013 can be applied over an edge of the electronic component orelectronic module 2002 at a area that is adjacent to the electronicconnector 2004 and/or the connection region 2012.

In some embodiments, additional layers of adhesives or coatings can beapplied over the coating material 2013 that has been applied tostrengthen the connection points. In some embodiments, additional layersof adhesives or coatings can be applied over the substrate, electronicmodules, connectors, electrical connections, and/or coating material2013. The additional layers of adhesives or coatings applied over thesubstrate, electronic modules, connectors, electrical connections,and/or coating material 2013 can be any of the adhesives or coatingsdescribed herein. In some embodiments, additional layers of adhesives orcoatings can be applied over the substrate, electronic modules,connectors, electrical connections, and/or coating material 2013 similarto the coating(s) described with reference to FIGS. 4-7.

In some embodiments, an additional non-stretchable or substantiallynon-stretchable coating or adhesive can be applied over components onthe substrate. For example, a non-stretchable or substantiallynon-stretchable coating or adhesive can be applied over one or moreportions of the substrate, electronic modules, connectors, electricalconnections, and/or coating material 2013. In some embodiments, theadditional layers of non-stretchable or substantially non-stretchablecoating or adhesive can be applied over the substrate, electronicmodules, connectors, electrical connections, and/or coating material2013 similar to the non-stretchable or substantially non-stretchablecoating or adhesive described with reference to FIGS. 4-7.

In some embodiments, a substantially stretchable or extensible coatingor adhesive can be applied uniformly over the wound facing surface ofthe substrate. The substantially stretchable or extensible coating oradhesive can be applied uniformly over the substrate, electronicmodules, connectors, electrical connections, and/or coating material2013. In some embodiments, the substantially stretchable or extensiblecoating or adhesive can be applied to the opposite side of the substrate(opposite the wound facing surface). The substrate can be encapsulatedin the substantially stretchable or extensible coating or adhesive asdescribed herein. For example, the sides of the substrate can also beencapsulated in the coating. The substantially stretchable or extensiblecoating or adhesive can be similar to the substantially stretchable orextensible coatings or adhesives described herein and especially asdescribed with reference to FIGS. 4-7.

In some embodiments, the substrate, electronic modules, connectors,electrical connections, and/or coating material 2013 can be covered withan additional adhesive or coating. At least one additional coating canbe applied to the side of the substrate supporting electroniccomponents. The at least one additional coating can also be applied tothe side of the substrate opposite the side of the substrate supportingelectronic components. The sides of the substrate can also beencapsulated in the at least one additional coating. In someembodiments, the at least one additional coating can be substantiallystretchable or extensible. In some embodiments, the at least oneadditional coating can be a biocompatible coating. In some embodiments,the at least one additional coating can be a hydrophobic coating.

As described previously with reference to FIGS. 5-7, the substrate 530can be coated with one or more coatings. FIGS. 22-23 illustratecoating(s) of a wound dressing according to some embodiments similar tothe coating(s) of the wound dressing described with reference to FIGS.5-7 previously. As described herein, one of the sides of a substrate2230 of the wound dressing can include a plurality of electroniccomponents 2202 protruding from the surface of the substrate 2230. Thisis illustrated, for example, in FIGS. 4A-4C where the electronic module402 protrudes from the wound facing surface of the substrate 530. As isshown in FIG. 22, coating 2240A can be applied to the side of thesubstrate supporting electronic components. As described herein, coating2240A can be biocompatible. Coating 2240A can be hydrophobic. Coating2240A can be substantially stretchable or extensible. In some cases, thecoating 2240A can have a thickness range of between 10 to 200 μm (about10 to 200 μm) thick. In some cases, the coating 2240A can have athickness range of between 80 to 130 μm (about 80 to 130 μm) thick.

As shown in FIG. 22, coating 2240B can be applied to the opposite sideof the substrate. This can be advantageous when a substrate is notbiocompatible or hydrophobic. Coating 2240B can be biocompatible.Coating 2240B can be hydrophobic. In some cases, the coating 2240B canbe a hydrophilic coating. Coating 2240B can be substantially stretchableor extensible. Coatings 2240A and 2240B can be the same or different.The substrate 2230 can be encapsulated in the coating as describedherein. Although not illustrated, the left and right sides of thesubstrate 2230 are also encapsulated in the coating. In some cases, thecoating 2240B can be an acrylated urethane and the cured coating can behydrophilic. In some cases, the coating 2240B can have a thickness rangeof between 10 to 200 μm (about 10 to 200 μm) thick. In some cases, thecoating 2240B can have a thickness range of between 80 to 130 μm (about80 to 130 μm) thick.

In some embodiments, an additional coating 2240C can be applied over theelectronic modules 2202 that protrude from the surface of the substrate2230 to ensure full coverage and coating of those components. Coating2240C can be substantially stretchable or extensible. Coatings 2240A,2240B, and/or 2240C can be the same or different. Providing anadditional layer of coating only over the electronic modules 2202 orother protruding components can ensure the electronic modules 2202 canbe covered by an adequate thickness of coating while maintaining a thin,consistent coverage over other areas where a thin coating can be helpful(e.g. over temperature sensor and impedance pads). In some cases, thecoating 2240C can be hydrophobic. In other cases, the coating 2240C canbe hydrophilic. In some cases, the substrate 2230 can by hydrophilic. Insome cases, the substrate 2230 can be hydrophobic. In some cases, thecoating 2240C can have a thickness of between 10 to 200 μm (about 10 to200 μm) thick. The coating 2240C can have a thickness range of between80 to 130 μm (about 80 to 130 μm) thick.

In other cases, both coatings 2240A and 2240C can have a combinedthickness that is between 10 to 200 μm (about 10 to 200 μm) thick. Bothcoatings 2240A and 2240C can have a combined thickness range of between80 to 130 μm (about 80 to 130 μm) thick.

In some cases, the coating 2240B can have a uniform or homogenousthickness (or substantially uniform or homogenous thickness) over thesubstrate including over the electronic components, electronicconnection, and/or electronic tracks.

FIG. 23 illustrates coating a wound dressing with three biocompatiblecoatings according to some embodiments. Electronic components 2302supported by the substrate 2330 can be coated with coating 2340A,particularly if the substrate 2330 is stretchable or substantiallystretchable. As described herein, coating 2340A can be non-stretchableor substantially non-stretchable to provide stress relief for theelectronic components (which may include electronic modules orelectronic connections). Coating 2340A can be applied on and around theelectronic components, electronic connections, or connectors aredescribed herein in reference to FIGS. 20-21. Coating 2340A can bebiocompatible. Coating 2340A can be hydrophobic.

Non-stretchable or substantially non-stretchable coating describedherein, such as the coating 2340A, can be formed from acrylated ormodified urethane material (such as, Henkel Loctite 3211). For example,coating can be one or more of Dymax 1901-M, Dymax 9001-E, Dymax 20351,Dymax 20558, Henkel Loctite 3211, or another suitable material. Coatingcan have viscosity from about 13,500 cP to 50,000 cP before being curedor from about 3,600 cP to about 6,600 cP before being cured. In somecases, coating can have viscosity of no more than about 50,000 cP.Coating can have hardness from about D40 to about D65 and/or linearshrinkage of about 1.5-2.5%. Coating can be transparent or substantiallytransparent to permit optical detection. Coating may be colorless orsubstantially colorless. Coating 2340A can be fluorescent. Coating canretain bond strength when subjected to sterilization, such as EtOsterilization.

As illustrated, coating 2340B can be applied to the remaining surface ofthe side of the substrate supporting the electronic components. Thecoating 2340B can be applied to the entire surface of the side of thesubstrate supporting the electronic components. In some cases, thecoating 2340B can have a thickness of between 10 to 200 μm (about 10 to200 μm) thick. In some cases, the coating 2340B can have a thicknessrange of between 80 to 130 μm (about 80 to 130 μm) thick.

Coating 2340B can also be applied to the opposite side of the substrate.Although not illustrated, the left and right sides of the substrate 2330are also encapsulated in the coating. Coating 2340B can bebiocompatible. Coating 2340B can be hydrophobic. Coating 2340B can besubstantially stretchable or extensible. Coating 2340B may be similar toany of the one or more flexible or substantially flexible coatingsdescribed herein. For example, coating 2340B may be formed fromacrylated urethane or its alternative, such as 1165-M Dymax, 1072-MDymax, Henkel Loctite 3381 or another suitable material.

In some cases, the coating 2340B on the side of the substrate supportingthe electronic components can be the same or different material than thecoating 2340B that coats the opposite side of the substrate. In somecases, the coating 2340B on one or both sides of the substrate can bethe same or different from coating 2340A.

In some embodiments, non-stretchable or substantially non-stretchablecoating may not be biocompatible. As illustrated in FIG. 23, theelectronic components 2302 supported by the substrate 2330 are coatedwith non-stretchable or substantially non-stretchable coating 2340A,which is not biocompatible. A second coating 2340B can be applied to theside of the substrate 2330 supporting the electronic components. Coating2340B can be applied over coating 2340A. Coating 2340B can also beapplied to the opposite side of the substrate. Although not illustrated,the left and right sides of the substrate 2330 are also encapsulated incoating 2340B. Coating 2340B can be biocompatible. Coating 2340B can behydrophobic. Coating 2340B can be substantially stretchable orextensible.

Coating a thin, flexible substrate with biocompatible material may benon-trivial because the substrate may need to be coated on the sidewhere electronic components are positioned and on the opposite side. Inaddition, the substrate may need to be coated evenly and comprehensively(for example, the substrate may be encapsulated by the biocompatiblecoating). In some embodiments, an additional coating 2340C can beapplied over the electronic modules 2302 that protrude from the surfaceof the substrate 2330 to ensure full coverage and coating of thosecomponents. Coating 2340C can be substantially stretchable orextensible. Coatings 2340B and 2340C can be the same or different.Providing an additional layer of coating only over the electronicmodules 2302 or other protruding components can ensure the electronicmodules 2302 can be covered by an adequate thickness of coating whilemaintaining a thin, consistent coverage over other areas where a thincoating can be helpful (e.g. over temperature sensor and impedancepads). In some case, coating 2340A, 2340B, and/or 2340C can bebiocompatible coatings. In some cases, coatings 2340A, 2340B, and/or2340C can all be the same coating or can all be different coatings. Insome cases, one or more of coatings 2340A, 2340B, and/or 2340C can bethe same coating material as one of the other coatings or one or more ofcoatings 2340A, 2340B, and/or 2340C can be a different material thananother coating. In some cases, multiple passes of one coat can be usedin place of using multiple different coatings on the substrate. Forexample, in some cases, multiple passes of coating 2340B can be used inplace of using both coating 2340A and 2340B. In some cases, multiplepasses of coating 2340B can be used in place of using both coating 2340Band 2340C. Multiple passes of any coating described herein can be usedto coat the substrate, electronic components, electronic connection,and/or electronic tracks. Multiple passes of a coating can avoid theformation of gaps in the coating. The multiple passes of a coatingapplication can control the thickness of one or more layer over thesubstrate, electronic components, electronic connection, and/orelectronic tracks. The multiple phases of the coating application canensure that there are no gaps in coverage over the substrate, electroniccomponents, electronic connection, and/or electronic tracks.

In some cases, a first side of the substrate can be coated with coating2340B. The second side of the substrate opposite the first side can becoated with coating 2340B or can be coated with a different coating.Additionally, the first side of the substrate can be coated with coating2340C over the electronic components and/or electronic connectors.

In some cases, a single layer of coating can be used. For example, asingle layer of coating 2340B can be used. In some cases, multiplelayers of coatings may not be used. In such cases, a single coating canbe used and applied with varying thickness. The non-homogenous thicknessof the coating can allow for a greater thickness applied over theelectronic components and/or electronic connectors while a less thicklayer of the same or a different coating can be applied over theremainder of the substrate. The non-homogenous thickness of coating canbe created using multiple layers of material applied, multiple passesused for application of the coating, and/or one pass of coating applyingvarying thickness of coating in discrete areas on the substrate and/orover the electronic components and/or electronic connectors.

In some cases, one or more of the coatings described herein can beapplied to the substrate as a liquid and the liquid can be cured onceapplied to the substrate. In some cases, the one or more coatings can besprayed onto the substrate. In some cases, spraying of the one or morecoatings can comprise spraying with compressed air or inert gas. In somecases, handling and curing of the coatings can occur under inertatmosphere techniques. In some cases, the coatings described herein canbe applied by spraying using pressure only (gas free).

The coating of the substrate, electronic components, and/or electronicconnections can be carried out in inert gas. The coated substrate,electronic components, and/or electronic connections can be cured ininert gas. In some cases, gases such as nitrogen, argon, and/or helium.The use of inert atmosphere techniques can substantially displace oxygenfrom the area immediately around the encapsulant and air junction. Insome cases, since some gases are lighter than air and others are heavierthan air, different spraying, curing, and/or handling techniques may beused depending on the gas selected. In some cases, this can be used withUV curing systems.

In some cases, the coated substrate, electronic components, and/orelectronic connections can be cured using any curing process typeincluding but not limited to UV, heat, and/or catalytic 2 part componentmix.

In some cases, the one or more coatings can be applied through extrusionand curtain coating (no atomization). In some cases, the coating isapplied with a measured dispensing for the coating and as describedherein can vary the amount and/or the thickness of the coatings. In somecases, a measured dispensing of any of the coatings can be used to coatthe substrate.

FIG. 24A illustrates an embodiment of a substrate 2430 with a thin layerof coating 2440B over the entire surface of the substrate 2430. Thecoating can be applied as thinly as possible over the substrate 2430 toprovide the insulation required for the device to function and insulateas required without interfering with the performance of the sensors. Asillustrated in FIG. 24A, the substrate 2430 includes electronic modules2402 that are taller or protrude further off the surface of thesubstrate 2430 than other components on the substrate surface. Theseprotruding components such as the electronic modules 2402 run the riskof protruding through the thin layer of coating 2440B, potentiallycausing exposed areas. Therefore, a uniform layer of coating can beapplied over the surface of the substrate 2430 and an additional layerof coating can be applied over the protruding or taller components suchas the electronic modules 2402 to ensure they have full coverage. Thisadditional layer of coating provides less potential for failure pointsto occur in the insulating layer. FIG. 24B illustrates an additionallayer of coating 2440C over the electronic modules 2402.

Other Variations

In some embodiments, one or more electronic components can be positionedon the side of a wound contact layer opposite the side that faces thewound. Systems and methods described herein are equally applicable tosuch wound contact layers. Although spraying the coating is describedabove, other suitable methods for applying the coating can be used incertain embodiments. Such methods can include one or more of dipcoating, spin coating, vapor deposition, chemical deposition,electrochemical deposition, roll-to-roll coating, laminating, adhering,welding (for instance, ultrasonic welding), curing by one or more oflight, UV, heat, or the like.

Although certain embodiments described herein relate to wound dressings,systems and methods disclosed herein are not limited to wound dressingsor medical applications. Systems and methods disclosed herein aregenerally applicable to electronic devices in general, such aselectronic devices that can be worn by or applied to a user.

Any value of a threshold, limit, duration, etc. provided herein is notintended to be absolute and, thereby, can be approximate. In addition,any threshold, limit, duration, etc. provided herein can be fixed orvaried either automatically or by a user. Furthermore, as is used hereinrelative terminology such as exceeds, greater than, less than, etc. inrelation to a reference value is intended to also encompass being equalto the reference value. For example, exceeding a reference value that ispositive can encompass being equal to or greater than the referencevalue. In addition, as is used herein relative terminology such asexceeds, greater than, less than, etc. in relation to a reference valueis intended to also encompass an inverse of the disclosed relationship,such as below, less than, greater than, etc. in relations to thereference value. Moreover, although blocks of the various processes maybe described in terms of determining whether a value meets or does notmeet a particular threshold, the blocks can be similarly understood, forexample, in terms of a value (i) being below or above a threshold or(ii) satisfying or not satisfying a threshold.

Features, materials, characteristics, or groups described in conjunctionwith a particular aspect, embodiment, or example are to be understood tobe applicable to any other aspect, embodiment or example describedherein unless incompatible therewith. All of the features disclosed inthis specification (including any accompanying claims, abstract anddrawings), or all of the steps of any method or process so disclosed,may be combined in any combination, except combinations where at leastsome of such features or steps are mutually exclusive. The protection isnot restricted to the details of any foregoing embodiments. Theprotection extends to any novel one, or any novel combination, of thefeatures disclosed in this specification (including any accompanyingclaims, abstract and drawings), or to any novel one, or any novelcombination, of the steps of any method or process so disclosed.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of protection. Indeed, the novel methods and systems describedherein may be embodied in a variety of other forms. Furthermore, variousomissions, substitutions and changes in the form of the methods andsystems described herein may be made. Those skilled in the art willappreciate that in some embodiments, the actual steps taken in theprocesses illustrated or disclosed may differ from those shown in thefigures. Depending on the embodiment, certain of the steps describedabove may be removed, others may be added. For example, the actual stepsor order of steps taken in the disclosed processes may differ from thoseshown in the figure. Depending on the embodiment, certain of the stepsdescribed above may be removed, others may be added. For instance, thevarious components illustrated in the figures may be implemented assoftware or firmware on a processor, controller, ASIC, FPGA, ordedicated hardware. Hardware components, such as controllers,processors, ASICs, FPGAs, and the like, can include logic circuitry.Furthermore, the features and attributes of the specific embodimentsdisclosed above may be combined in different ways to form additionalembodiments, all of which fall within the scope of the presentdisclosure.

Although the present disclosure includes certain embodiments, examplesand applications, it will be understood by those skilled in the art thatthe present disclosure extends beyond the specifically disclosedembodiments to other alternative embodiments or uses and obviousmodifications and equivalents thereof, including embodiments which donot provide all of the features and advantages set forth herein.Accordingly, the scope of the present disclosure is not intended to belimited by the specific disclosures of preferred embodiments herein, andmay be defined by claims as presented herein or as presented in thefuture.

Conditional language, such as “can,” “could,” “might,” or “may,” unlessspecifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements, or steps. Thus, such conditional language is notgenerally intended to imply that features, elements, or steps are in anyway required for one or more embodiments or that one or more embodimentsnecessarily include logic for deciding, with or without user input orprompting, whether these features, elements, or steps are included orare to be performed in any particular embodiment. The terms“comprising,” “including,” “having,” and the like are synonymous and areused inclusively, in an open-ended fashion, and do not excludeadditional elements, features, acts, operations, and so forth. Also, theterm “or” is used in its inclusive sense (and not in its exclusivesense) so that when used, for example, to connect a list of elements,the term “or” means one, some, or all of the elements in the list.Further, the term “each,” as used herein, in addition to having itsordinary meaning, can mean any subset of a set of elements to which theterm “each” is applied.

Conjunctive language such as the phrase “at least one of X, Y, and Z,”unless specifically stated otherwise, is otherwise understood with thecontext as used in general to convey that an item, term, etc. may beeither X, Y, or Z. Thus, such conjunctive language is not generallyintended to imply that certain embodiments require the presence of atleast one of X, at least one of Y, and at least one of Z.

Language of degree used herein, such as the terms “approximately,”“about,” “generally,” and “substantially” as used herein represent avalue, amount, or characteristic close to the stated value, amount, orcharacteristic that still performs a desired function or achieves adesired result. For example, the terms “approximately”, “about”,“generally,” and “substantially” may refer to an amount that is withinless than 10% of, within less than 5% of, within less than 1% of, withinless than 0.1% of, and within less than 0.01% of the stated amount. Asanother example, in certain embodiments, the terms “generally parallel”and “substantially parallel” refer to a value, amount, or characteristicthat departs from exactly parallel by less than or equal to 15 degrees,10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree.

The scope of the present disclosure is not intended to be limited by thespecific disclosures of preferred embodiments in this section orelsewhere in this specification, and may be defined by claims aspresented in this section or elsewhere in this specification or aspresented in the future. The language of the claims is to be interpretedbroadly based on the language employed in the claims and not limited tothe examples described in the present specification or during theprosecution of the application, which examples are to be construed asnon-exclusive.

1. A method for coating a wound dressing, the method comprising:applying a first coating on a first side of a substantially flexiblesubstrate of the wound dressing, the first side of the substratesupporting a plurality of electronic components, electronic tracks, anda plurality of connectors between the electronic components andelectronic tracks, wherein the first coating is applied to at least oneconnector of the plurality of connectors to reinforce the at least oneconnector; applying a second coating on the first side of the substrate;coating a second side of the substrate opposite the first side with athird coating; and coating at least some of the plurality of theelectronic components with a fourth coating.
 2. The method of claim 1,wherein the flexible substrate is a flexible and extensible substrate.3. The method of claim 1, further comprising applying the first coatingto a discrete area of the substrate supporting and surrounding at leastone electronic component or electronic track electrically connected bythe at least one connector to reinforce the area of the substrate. 4.The method of claim 1, wherein the first coating is applied to an areasurrounding a perimeter of an electronic component associated with theat least one connector.
 5. The method of claim 1, wherein the firstcoating is applied to an area on a first side of an electronic componentwhere the at least one connector is positioned and not applied on asecond side of the electronic components where the at least oneconnector is not positioned. 6.-7. (canceled)
 8. The method of claim 1,wherein the second coating comprises a hydrophobic coating.
 9. Themethod of claim 1, wherein the second coating comprises a hydrophiliccoating. 10.-11. (canceled)
 12. The method of claim 1, wherein thefirst, second, third, and/or fourth coatings comprise a biocompatiblecoating. 13.-21. (canceled)
 22. The method of claim 1, furthercomprising encapsulating the substrate with the second coating.
 23. Themethod of claim 1, wherein the first coating is substantiallynon-stretchable.
 24. The method of claim 1, wherein one or more of thesecond, third and fourth coatings is substantially stretchable. 25.-26.(canceled)
 27. The method of claim 1, further comprising coating atleast some of the plurality of the electronic components with multiplelayers of the first, second, third, and/or fourth coating. 28.-29.(canceled)
 30. The method of claim 1, wherein handling and curing of thematerial occurs under inert atmosphere techniques.
 31. (canceled) 32.The method of claim 1, wherein the first coating has viscosity of nomore than about 50,000 centipoise.
 33. The method of claim 1, whereinthe first coating is applied to an area around a perimeter of anelectronic component at areas not associated with the at least oneconnector.
 34. The method of claim 1, wherein the first coating isapplied to the edge of a component of the plurality of electroniccomponents to reinforce the edge of the component and the at least oneconnector of the plurality of connectors.
 35. A wound dressing apparatuscomprising: a substantially flexible substrate comprising a first sideof the substrate supporting a plurality of electronic components,electronic tracks, and a plurality of connectors between the electroniccomponents and electronic tracks, a first coating on the first side ofthe substrate applied to at least one connector of the plurality ofconnectors to reinforce the at least one connector; a second coating onthe first side of the substrate; a third coating on a second side of thesubstrate opposite the first side; and a fourth coating applied over atleast some of the plurality of the electronic components.
 36. The wounddressing apparatus of claim 35, wherein the flexible substrate is aflexible and extensible substrate.
 37. The wound dressing apparatus ofclaim 35, wherein the first coating is applied to a discrete area of thesubstrate supporting and surrounding at least one electronic componentor electronic track electrically connected by the at least one connectorto reinforce the area of the substrate.
 38. The wound dressing apparatusof claim 35, wherein the first coating is applied to an area surroundinga perimeter of an electronic component associated with the at least oneconnector.
 39. The wound dressing apparatus of claim 35, wherein thefirst coating is applied to an area on a first side of an electroniccomponent where the at least one connector is positioned and not appliedon a second side of the electronic components where the at least oneconnector is not positioned.
 40. The wound dressing apparatus of claim35, wherein the first coating is substantially non-stretchable.
 41. Thewound dressing apparatus of claim 35, wherein one or more of the second,third and fourth coatings is substantially stretchable. 42.-51.(canceled)